Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	$ 25,447	$ 26,156
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	19,334	19,838
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	6,113	6,318
Fair Value, Inputs, Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	25,447	26,156
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	19,334	19,838
Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	6,113	6,318
Fair Value, Inputs, Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Fair Value Disclosure	$ 0	$ 0