Quarterly report pursuant to Section 13 or 15(d)

Investments in Marketable Securities (Held to Maturity Securities, by Maturity) (Details)

v2.4.1.9
Investments in Marketable Securities (Held to Maturity Securities, by Maturity) (Details) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities $ 108,000us-gaap_AvailableForSaleSecurities $ 107,000us-gaap_AvailableForSaleSecurities
Letters of Credit Outstanding, Amount 1,400,000us-gaap_LettersOfCreditOutstandingAmount  
Held-to-maturity Securities, Current 316,000us-gaap_HeldToMaturitySecuritiesCurrent 534,000us-gaap_HeldToMaturitySecuritiesCurrent
Held-to-maturity Securities, Noncurrent 1,270,000us-gaap_HeldToMaturitySecuritiesNoncurrent 1,057,000us-gaap_HeldToMaturitySecuritiesNoncurrent
Held-to-maturity Securities, Total 1,586,000us-gaap_HeldToMaturitySecurities 1,591,000us-gaap_HeldToMaturitySecurities
Mutual Funds [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities 60,000us-gaap_AvailableForSaleSecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_EquityFundsMember
59,000us-gaap_AvailableForSaleSecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_EquityFundsMember
Cash/Money Market Accounts [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities 48,000us-gaap_AvailableForSaleSecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
48,000us-gaap_AvailableForSaleSecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
Held-to-maturity Securities, Current 82,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
204,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
Held-to-maturity Securities, Noncurrent 0us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
0us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
Held-to-maturity Securities, Total 82,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
204,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MoneyMarketFundsMember
US Treasury Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Held-to-maturity Securities, Current 105,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
105,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
Held-to-maturity Securities, Noncurrent 1,178,000us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
965,000us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
Held-to-maturity Securities, Total 1,283,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
1,070,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USTreasurySecuritiesMember
US Government Agencies Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Held-to-maturity Securities, Current 129,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember
225,000us-gaap_HeldToMaturitySecuritiesCurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Held-to-maturity Securities, Noncurrent 92,000us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember
92,000us-gaap_HeldToMaturitySecuritiesNoncurrent
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Held-to-maturity Securities, Total $ 221,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember
$ 317,000us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentAgenciesDebtSecuritiesMember