Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Benefit for change in tax rate and tax laws, value	$ (115,000)	$ 802,000	$ 9,543,000
Nondeductible expense, other	745,000	(893,000)	6,216,000
Benefit for tax rate differential	3,517,000	6,695,000	2,249,000
Income tax expense	33,216,000	46,944,000	19,736,000
Income tax expense (benefit) recognized directly to equity	6,200,000	300,000	(8,500,000)
Deferred tax asset not recognized, deductible temporary differences due to subsidiaries	14,800,000	11,800,000	17,800,000
Deferred tax liability due to subsidiaries for which a dividend distribution is expected	1,700,000	1,800,000	2,200,000
Reduction in deferred tax liabilities following U.S. tax reform			8,800,000
Reduction in deferred tax assets following U.S. tax reform			400,000
Income tax penalties accrued	0	0	0
Interest on income taxes accrued	500,000	500,000	900,000
Income tax penalties and interest accrued	$ 4,000,000.0	$ 3,400,000	$ 2,900,000
German entities
Income Tax Contingency [Line Items]
Corporate income tax rate	15.00%
Solidarity surcharge	0.825%	0.825%	0.825%
Solidarity surcharge rate on the corporate income tax rate	5.50%	5.50%	5.50%
Trade tax rate	16.18%	16.18%	16.18%
Overall tax rate	32.00%	32.00%	32.00%
Foreign Tax Authority | United States
Income Tax Contingency [Line Items]
Benefit for change in tax rate and tax laws, value			$ (8,800,000)
Foreign Tax Authority | Brazil
Income Tax Contingency [Line Items]
Nondeductible expense, other	$ 2,300,000	$ 1,600,000	$ 1,400,000
Foreign Tax Authority | South Korea
Income Tax Contingency [Line Items]
Benefit for tax rate differential		$ 6,300,000