Significant Accounting Policies - Revisions to Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets	$ 56,662		$ 71,049
Accrued liabilities	119,841	$ 102,640	102,976
Deferred tax liabilities	10,785		5,566
Other liabilities	34,154		37,209
Liabilities	1,759,600		1,772,670
Retained earnings	619,448	$ 566,608	569,215	$ 508,722	$ 420,659
Accumulated other comprehensive loss	(253,741)		(245,937)	(197,974)	(242,548)
Stockholders' Equity Attributable to Parent	856,175		824,806
Noncontrolling interests	19,807		26,669
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 875,982		851,475	852,101	716,493
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets			70,007
Accrued liabilities			98,907
Deferred tax liabilities			8,233
Other liabilities			29,542
Liabilities			1,763,601
Retained earnings			576,025	511,367	425,972
Accumulated other comprehensive loss			(246,088)	(197,631)	(242,563)
Stockholders' Equity Attributable to Parent			831,465
Noncontrolling interests			28,037
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			859,502	855,089	721,791
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets			1,042
Accrued liabilities			4,069
Deferred tax liabilities			(2,667)
Other liabilities			7,667
Liabilities			9,069
Retained earnings			(6,810)	(2,645)	(5,313)
Accumulated other comprehensive loss			151	(343)	15
Stockholders' Equity Attributable to Parent			(6,659)
Noncontrolling interests			(1,368)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ (8,027)	$ (2,988)	$ (5,298)