Fair Value Measurement (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 0
Assets Held-for-sale, Long Lived, Fair Value Disclosure	4,209	$ 4,134
Quoted prices in active markets for identical assets (level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure	0	0
Signifcant other observable inputs (level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure	0	0
Significant unobservable inputs (level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure	4,209	4,134
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	27,720	41,233
Fair Value, Measurements, Recurring [Member] | Significant unobservable inputs (level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Nontaxable Municipal Notes [Member] | Fair Value, Measurements, Recurring [Member] | Quoted prices in active markets for identical assets (level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	3,504	8,785
Nontaxable Municipal Notes [Member] | Fair Value, Measurements, Recurring [Member] | Signifcant other observable inputs (level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 24,216	$ 32,448