Income Taxes - Narrative (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Permanently reinvested earnings of non-U.S. subsidiaries	$ 18,200,000			$ 18,200,000	$ 350,000,000
Unrecognized deferred income tax liabilities on currently permanently reinvested earnings	3,700,000			3,700,000
Foreign earnings repatriated				135,000,000	3,300,000	$ 28,800,000
Incremental income tax expense (benefit)				0	(6,400,000)	2,700,000
Transition tax for accumulated foreign earnings, provisional liability	26,500,000			26,500,000	30,300,000
Tax Cuts and Jobs Act of 2017, one time transition tax for accumulated foreign earnings, income tax expense				100,000
Tax Cuts and Jobs Act of 2017, income tax expense (benefit)				3,900,000
Tax Cuts and Jobs Act of 2017, change in tax rate, income tax benefit	1,100,000			41,700,000	40,600,000
Tax Cuts and Jobs Act of 2017, provisional increase, deferred tax liability			$ 7,800,000		9,200,000
Tax Cuts and Jobs Act of 2017, adjustment, deferred income tax expense		$ 0	$ 1,400,000		9,200,000
Tax Cuts and Jobs Act of 2017, permanent reinvestment, deferred tax liability	9,100,000
Accrued interest related to uncertain tax positions	100,000			100,000	100,000	100,000
Accrued penalties related to uncertain tax positions	0			0	0	100,000
Unrecognized tax benefits that would affect our effective tax rate	3,000,000			3,000,000	900,000	$ 1,800,000
Loss carry forwards for U.S. federal	1,300,000			1,300,000	2,400,000
Loss carry forwards for non-U.S.	29,500,000			29,500,000	24,500,000
Operating loss and credit carry forwards	15,800,000			15,800,000	6,700,000
Operating loss carryforwards, valuation allowance	600,000			600,000	100,000
Capital loss carryforwards	12,754,000			12,754,000	12,853,000
Federal
Income Tax Disclosure [Line Items]
Capital loss carryforwards	46,100,000			46,100,000	46,000,000
Capital loss carryforwards, valuation allowance	9,700,000			9,700,000	9,700,000
State and Local
Income Tax Disclosure [Line Items]
Capital loss carryforwards	62,700,000			62,700,000	62,700,000
Capital loss carryforwards, valuation allowance	800,000			800,000	800,000
Foreign
Income Tax Disclosure [Line Items]
Capital loss carryforwards	13,400,000			13,400,000	14,200,000
Minimum
Income Tax Disclosure [Line Items]
Unrecognized tax benefits possible change	0			0
Maximum
Income Tax Disclosure [Line Items]
Unrecognized tax benefits possible change	1,000,000			1,000,000
Other current assets
Income Tax Disclosure [Line Items]
Prepaid taxes	$ 8,300,000			$ 8,300,000	$ 40,900,000