Investments and Fair Value Measurements (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Investments and Fair Value Measurements [Abstract]
Asset impairment charges		$ 1,456	$ 350	$ 1,501	$ 2,350
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		54,443		54,443		$ 59,520
Unrealized Losses		(285)		(285)		(18)
Aggregate Fair Value		54,158		54,158		59,502
Financial assets [Abstract]
Municipal securities	[1]	54,158		54,158		59,502
Foreign currency exchange contracts						14
Total financial assets		54,158		54,158		59,516
Financial liabilities [Abstract]
Foreign currency exchange contracts						1,359
Total financial liabilities						1,359
Short Term Municipal Securities Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[2]	54,443		54,443		59,520
Unrealized Losses	[2]	(285)		(285)		(18)
Aggregate Fair Value	[2]	54,158		54,158		59,502
Level 1 [Member]
Financial assets [Abstract]
Municipal securities	[1]	54,158		54,158		59,502
Foreign currency exchange contracts						0
Total financial assets		54,158		54,158		59,502
Financial liabilities [Abstract]
Foreign currency exchange contracts						0
Total financial liabilities						0
Level 2 [Member]
Financial assets [Abstract]
Municipal securities	[1]	0		0		0
Foreign currency exchange contracts						14
Total financial assets		0		0		14
Financial liabilities [Abstract]
Foreign currency exchange contracts						1,359
Total financial liabilities						1,359
Level 3 [Member]
Financial assets [Abstract]
Municipal securities	[1]	0		0		0
Foreign currency exchange contracts						0
Total financial assets		$ 0		$ 0		0
Financial liabilities [Abstract]
Foreign currency exchange contracts						0
Total financial liabilities						$ 0

[1] At September 30, 2015 and December 31, 2014, municipal securities consisted solely of holdings in short-term municipal security funds.

[2] Do not have a set maturity date.