Income Taxes (Effective Income Tax Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income tax expense and rate attributable to:
Federal income tax rate	$ 25,058	$ 13,683	$ 6,363
State income tax rate, net of federal benefit	5,983	1,271	53
Foreign income tax rate differential	1,994	7,630	(11,768)
Enacted changes in tax law	634	495	17,645
GILTI, net	7,585	3,443	0
Non-deductible / non-taxable items	6,727	3,602	6,006
Change in valuation allowance	(33,691)	(5,304)	24,400
U.S. tax on foreign earnings	0	0	(32,427)
Foreign tax credits	(12,541)	(7,709)	(7,980)
Uncertain tax positions	278	(1,696)	1,054
Audit settlements	391	183	354
Share-based compensation	(2,715)	764	882
Deferred income tax account adjustments	0	(25)	2,679
Other	122	(1,617)	681
Total income tax expense (benefit)	$ (175)	$ 14,720	$ 7,942
Income tax expense and rate attributable to (percent):
Federal income tax rate (percent)	21.00%	21.00%	35.00%
State income tax rate, net of federal benefit (percent)	5.00%	2.00%	0.30%
Foreign differential (percent)	1.70%	11.60%	(64.70%)
Enacted changes in tax law (percent)	0.50%	0.80%	97.10%
GILTI, net (percent)	6.40%	5.30%	0.00%
Non-deductible / non-taxable items (percent)	5.70%	5.50%	33.00%
Change in valuation allowance (percent)	(28.20%)	(8.10%)	134.20%
U.S. tax on foreign earnings (percent)	0.00%	0.00%	(178.40%)
Foreign tax credits (percent)	(10.50%)	(11.90%)	(43.90%)
Uncertain tax positions (percent)	0.20%	(2.60%)	5.80%
Audit settlements (percent)	0.30%	0.30%	1.90%
Share-based compensation (percent)	(2.30%)	1.20%	4.90%
Deferred income tax account adjustments (percent)	0.00%	0.00%	14.70%
Other (percent)	0.10%	(2.50%)	3.80%
Effective tax rate (percent)	(0.10%)	22.60%	43.70%