Restructuring Charges (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Restructuring Charges
Balance at the beginning of the period	$ 2,224
Balance at the end of the period	1,254
Restructuring Plan 2011 | Consolidation of leased facilities
Restructuring Charges
Balance at the beginning of the period	833
Utilized - cash	(561)
Balance at the end of the period	272
Restructuring Plan 2010 | Consolidation of leased facilities
Restructuring Charges
Balance at the beginning of the period	1,391
Utilized - cash	(409)
Balance at the end of the period	$ 982