Taxes - Additional Information (Details) - USD ($)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Domestic income from continuing operations before taxes		$ 39,042,000	$ 30,345,000	$ 23,939,000
Foreign income from continuing operations before taxes		195,532,000	236,119,000	$ 138,138,000
Tax expense from write down of deferred tax assets		3,240,000	12,523,000
Estimated tax expense		11,028,000	101,379,000
One-time transition tax payable		$ 90,351,000
Decrease in tax expense			$ 3,843,000
Income tax rate		21.00%	35.00%	35.00%
Cash		$ 104,655,000	$ 97,951,000
Foreign tax rate differential		9.00%	27.00%	17.00%
Reduction of income tax expense for adoption of ASU 2016-09		$ 8,488,000	$ 38,569,000	$ 11,889,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other		1,847,000	$ 2,502,000
Deferred Tax Assets, State Taxes		$ 620,000
Discrete tax benefit related to employee stock option exercises		4.00%	14.00%	7.00%
Net cash provided by operating activities		$ 223,454,000	$ 224,323,000	$ 182,081,000
Net cash used in financing activities		209,904,000	100,121,000	29,231,000
Income tax penalties and interest expense		91,000	71,000	92,000
Deferred tax liabilities, gross		8,134,000	7,516,000
Reserve for income taxes		7,106,000	6,488,000
Unrecognized tax benefit shown as a reduction to noncurrent deferred tax assets		1,028,000	1,028,000
Interest and penalties, gross		840,000	767,000
Minimum decrease in income tax expense due to release in reserves		1,200,000
Maximum decrease in income tax expense due to release in reserves			1,300,000
Net non-current deferred tax liabilities		(962,000)	(312,000)
Non deductible federal and state liabilities		44,000	87,000
Income tax paid net		$ 41,430,000	$ 11,802,000	20,748,000
Open Tax Year State Authorities		2013 through 2016
Open tax year United States Internal Revenue Service		2013 through 2016
Open tax year, various taxing authorities		2012 through 2016
Tax Years Covered Through Advanced Pricing Agreement			2006 through 2011
Tax years for APA agreement		Between 2014 and 2018
State research and experimentation tax carryforwards		2014 through 2016
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Deferred tax assets, valuation allowance		$ 803,000
State Research And Experimentation [Member]
Tax Credit Carryforward [Line Items]
Deferred tax assets, tax credit carryforwards, research		8,423,000
Other Than the U.S [Member]
Tax Credit Carryforward [Line Items]
Cash		$ 446,346,000	$ 498,653,000
Accounting Standards Update 2016-16 [Member]
Tax Credit Carryforward [Line Items]
Cumulative effect on retained earnings, net of tax	$ 5,961,000
Accounting Standards Update 2016-09, Statutory Tax Withholding Component [Member]
Tax Credit Carryforward [Line Items]
Net cash used in financing activities			$ 9,964,000	$ 7,871,000