Restructuring and Other Related Costs Amount of restructuring and other related costs recognized during the year (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, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs	$ 0	$ 3,478	$ 240	$ 49	$ 3,604	$ 566	$ 0	$ 47		$ 3,767	$ 4,217	$ 3,645
Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs										1,353	2,484	900
Restructuring reserve accrual adjustment										(375)
Restructuring Reserve	1,147				2,202				$ 2,031	1,147	2,202	2,031	$ 4,568
Real Estate Exit and Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs										2,301	1,719	2,513
Restructuring reserve accrual adjustment										375
Restructuring Reserve	3,314				2,935				2,600	3,314	2,935	2,600	769
Asset Write-offs and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs										113	14	232
Restructuring Reserve	0				0				0	0	0	0	0
Accrued Restructuring Liability [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs										3,767	4,217	3,645
Restructuring reserve accrual adjustment										0
Restructuring Reserve	4,461				5,137				4,631	4,461	5,137	$ 4,631	$ 5,337
Other Current Liabilities [Member] | Accrued Restructuring Liability [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	3,500				4,100					3,500	4,100
Other Noncurrent Liabilities [Member] | Accrued Restructuring Liability [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 1,000				1,000					1,000	1,000
2016 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs		3,243
2016 Restructuring Plan [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs		1,200
2016 Restructuring Plan [Member] | Real Estate Exit and Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs		1,900
2016 Restructuring Plan [Member] | Asset Write-offs and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs		$ 100
2015 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs					3,604
2015 Restructuring Plan [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs					2,500
Restructuring reserve accrual adjustment										(375)
2015 Restructuring Plan [Member] | Real Estate Exit and Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs					$ 1,100
Restructuring reserve accrual adjustment						$ 500				$ 400
2014 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs									3,645
2014 Restructuring Plan [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs									1,800
2014 Restructuring Plan [Member] | Real Estate Exit and Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs									1,600
Restructuring reserve accrual adjustment											$ 600
2014 Restructuring Plan [Member] | Asset Write-offs and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs									$ 200