Income Taxes (Effective Income Tax Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal	$ 13,683	$ 6,363	$ (2,524)
Federal income tax rate (percent)	21.00%	35.00%	35.00%
State, net of federal benefit	$ 1,271	$ 53	$ (202)
State income tax rate, net of federal benefit (percent)	2.00%	0.30%	2.80%
Foreign differential	$ 7,630	$ (11,768)	$ (12,624)
Foreign differential (percent)	11.60%	(64.70%)	175.00%
Enacted changes in tax law	$ 495	$ 17,645	$ 0
Enacted changes in tax law (percent)	0.80%	97.10%	0.00%
Effective Income Tax Rate Reconciliation, Global Intangible Low-tax Income, Amount	$ 3,443	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Global Intangible Low-tax Income, Percent	5.30%	0.00%	0.00%
Non-deductible / non-taxable items	$ 3,602	$ 6,006	$ 2,694
Non-deductible / non-taxable items (percent)	5.50%	33.00%	(37.40%)
Change in valuation allowance	$ (5,304)	$ 24,400	$ 16,041
Change in valuation allowance (percent)	(8.10%)	134.20%	(222.40%)
U.S. tax on foreign earnings	$ 0	$ (32,427)	$ 23,130
U.S. tax on foreign earnings (percent)	0.00%	(178.40%)	(320.60%)
Foreign tax credits	$ (7,709)	$ (7,980)	$ (18,581)
Foreign tax credits (percent)	(11.90%)	(43.90%)	257.60%
Uncertain tax positions	$ (1,696)	$ 1,054	$ 19
Uncertain tax positions (percent)	(2.60%)	5.80%	(0.30%)
Audit settlements	$ 183	$ 354	$ 253
Audit settlements (percent)	0.30%	1.90%	(3.50%)
Share-based compensation	$ 764	$ 882	$ 2,120
Stock compensation windfall / shortfall (percent)	1.20%	4.90%	(29.40%)
Deferred income tax account adjustments	$ (25)	$ 2,679	$ (842)
Deferred income tax account adjustments (percent)	0.00%	14.70%	11.70%
Other	$ (1,617)	$ 681	$ (203)
Other (percent)	(2.50%)	3.80%	2.80%
Income tax expense	$ 14,720	$ 7,942	$ 9,281
Effective tax rate (percent)	22.60%	43.70%	(128.70%)