Restructuring and Other Related Costs Restructuring plan provision summary (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Restructuring Charges	$ 0	$ 3,478	$ 240	$ 49	$ 3,604	$ 566	$ 0	$ 47	$ 3,767	$ 4,217	$ 3,645
Employee Severance and Related Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning				2,202				2,031	2,202	2,031	4,568
Cash Payments									(1,785)	(2,160)	(3,437)
Restructuring Charges									1,353	2,484	900
Non-cash payments									(248)	(153)	0
Restructuring Reserve, Ending	1,147				2,202				1,147	2,202	2,031
Restructuring reserve accrual adjustment									(375)
Real Estate Exit and Contract Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning				2,935				2,600	2,935	2,600	769
Cash Payments									(2,297)	(1,384)	(682)
Restructuring Charges									2,301	1,719	2,513
Non-cash payments									0	0	0
Restructuring Reserve, Ending	3,314				2,935				3,314	2,935	2,600
Restructuring reserve accrual adjustment									375
Asset Write-offs and Related Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning				0				0	0	0	0
Cash Payments									0	0	0
Restructuring Charges									113	14	232
Non-cash payments									(113)	(14)	(232)
Restructuring Reserve, Ending	0				0				0	0	0
Accrued Restructuring Liability [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning				$ 5,137				$ 4,631	5,137	4,631	5,337
Cash Payments									(4,082)	(3,544)	(4,119)
Restructuring Charges									3,767	4,217	3,645
Non-cash payments									(361)	(167)	(232)
Restructuring Reserve, Ending	$ 4,461				$ 5,137				4,461	$ 5,137	$ 4,631
Restructuring reserve accrual adjustment									$ 0