Income Taxes (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
Income Taxes [Abstract]
Undistributed Earnings of Foreign Subsidiaries	$ 281,000								$ 281,000
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries	26,600								26,600
Operating Loss Carryforwards	38,800								38,800
Operating Loss Carryforwards, Expiring in Next Three Years	3,500								3,500
Operating Loss Carryforwards, Expiring in Years Four, Five and Six	5,000								5,000
Operating Loss Carryforwards, Expiring in Years Seven, Eight and Nine	22,000								22,000
Operating Loss Carryforwards, Expiring Thereafter	4,600								4,600
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	3,700								3,700
Expired net operating loss carryforwards	100								100
Current Federal Tax Expense (Benefit)									(2,469)	$ 17,257	$ 44,350
Current Foreign Tax Expense (Benefit)									16,533	14,629	23,546
Current State and Local Tax Expense (Benefit)									600	1,979	4,727
Current Income Tax Expense (Benefit)									14,664	33,865	72,623
Deferred Federal Income Tax Expense (Benefit)									1,844	(2,905)	2,801
Deferred Foreign Income Tax Expense (Benefit)									(5,845)	2,947	1,675
Deferred State and Local Income Tax Expense (Benefit)									85	(149)	206
Deferred Income Tax Expense (Benefit)									(3,916)	(107)	4,682
Income Tax Expense (Benefit)	3,607	$ 2,081	$ 671	$ 4,389	$ 4,658	$ 9,753	$ 10,075	$ 9,272	10,748	33,758	77,305
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense									600	(500)	(1,100)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2,700				2,000				2,700	2,000	2,500
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 1,200				$ 2,400				$ 1,200	$ 2,400	$ 800