Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Line Items]
Tax Cuts and Jobs Act of 2017, income tax benefit	$ 100,000
Tax Cuts and Jobs Act of 2017, change in tax rate, income tax benefit	40,600,000
Tax Cuts and Jobs Act of 2017, one time transition tax for accumulated foreign earnings, income tax expense	30,300,000
Tax Cuts and Jobs Act of 2017,accumulated foreign earnings	779,000,000	$ 779,000,000
Tax Cuts and Jobs Act of 2017, tax planning strategies, income tax expense	10,200,000
Permanently reinvested earnings of non-U.S. subsidiaries	350,000,000	350,000,000	$ 670,000,000
Unrecognized deferred income tax liabilities on currently permanently reinvested earnings	$ 8,200,000	8,200,000
Foreign earnings repatriated		3,300,000	28,800,000	$ 14,300,000
Incremental income tax expense (benefit)		(6,400,000)	2,700,000	300,000
Tax Cuts and Jobs Act of 2017, provisional increase, deferred tax liability		9,200,000
Tax Cuts and Jobs Act of 2017, adjustment, deferred income tax expense		9,200,000
Tax Cuts and Jobs Act of 2017, permanent reinvestment, deferred tax liability		$ 8,200,000
Tax Cuts and Jobs Act of 2017, global intangible low taxed income, benchmark, percent	10.00%	10.00%
Tax Cuts and Jobs Act of 2017, provisional increase, income tax expense		$ 1,000,000
Accrued interest related to uncertain tax positions	$ 100,000	100,000	100,000	200,000
Accrued penalties related to uncertain tax positions	0	0	100,000	300,000
Unrecognized tax benefits that would affect our effective tax rate	900,000	900,000	1,800,000	$ 3,000,000
Loss carry forwards for U.S. federal	2,400,000	2,400,000	3,500,000
Loss carry forwards for non-U.S.	24,500,000	24,500,000	25,600,000
Operating loss and credit carry forwards	6,700,000	6,700,000	33,100,000
Operating loss carryforwards, valuation allowance	100,000	100,000	1,300,000
Capital loss carryforwards	12,853,000	12,853,000	18,668,000
Federal
Income Tax Disclosure [Line Items]
Capital loss carryforwards	46,000,000	46,000,000	70,100,000
Capital loss carryforwards, valuation allowance	9,700,000	9,700,000	18,700,000
State and Local
Income Tax Disclosure [Line Items]
Capital loss carryforwards	62,700,000	62,700,000	70,100,000
Capital loss carryforwards, valuation allowance	800,000	800,000	700,000
Foreign
Income Tax Disclosure [Line Items]
Capital loss carryforwards	14,200,000	14,200,000	700,000
Minimum
Income Tax Disclosure [Line Items]
Unrecognized tax benefits possible change	0	0
Maximum
Income Tax Disclosure [Line Items]
Unrecognized tax benefits possible change	1,700,000	1,700,000
Other current assets
Income Tax Disclosure [Line Items]
Prepaid taxes	40,900,000	$ 40,900,000	$ 42,200,000
Accrued liabilities
Income Tax Disclosure [Line Items]
Tax Cuts and Jobs Act of 2017, one time transition tax for accumulated foreign earnings, income tax expense	2,400,000
Other noncurrent liabilities
Income Tax Disclosure [Line Items]
Tax Cuts and Jobs Act of 2017, one time transition tax for accumulated foreign earnings, income tax expense	$ 27,900,000