Restructuring Restructuring Plan (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) employee	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) employee	Dec. 31, 2013 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 286	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 286	$ 0	$ 391
Restructuring Reserve, Current	273				0				$ 273	0
2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of Positions Eliminated (in employee) | employee									7
Restructuring Reserve					0					0
Restructuring charges									$ 300
Payments for Restructuring									(13)
Restructuring Reserve, Current	$ 273								$ 273
2014 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of Positions Eliminated (in employee) | employee											44
Restructuring Reserve											$ 701	$ 0
Restructuring charges										0	1,841
Payments for Restructuring										(701)	(1,140)
Restructuring Reserve, Current					$ 0					$ 0	$ 701