Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance		$ 390,472
Shareholders' Equity Attributable to Parent, Ending Balance	$ 411,831	411,831
Disproportionate tax effect	14,600	14,600
Deferred taxes provided for basis difference in foreign subsidiaries	0	0
Accumulated Other Comprehensive Loss, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	(37,384)	(33,595)
Other comprehensive income before reclassification	3,443	(4,218)
Amounts reclassified from accumulated other comprehensive loss, net	605	4,477
Net current period other comprehensive income	4,048	259
Shareholders' Equity Attributable to Parent, Ending Balance	(33,336)	(33,336)
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	(47,554)	(24,374)
Other comprehensive income before reclassification	(1,144)	(24,324)
Net current period other comprehensive income	(1,144)	(24,324)
Shareholders' Equity Attributable to Parent, Ending Balance	(48,698)	(48,698)
Deferred income tax expense (benefit)	(5,254)	(5,254)	$ (5,090)	$ (5,339)
Deferred tax expense before reclassification	(164)	85
Unrealized gains on interest rate swap and foreign currency forward contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	10,170	(9,221)
Other comprehensive income before reclassification	4,587	20,106
Amounts reclassified from accumulated other comprehensive loss, net	605	4,477
Net current period other comprehensive income	5,192	24,583
Shareholders' Equity Attributable to Parent, Ending Balance	15,362	15,362
Deferred income tax expense (benefit)	23,663	23,663	$ 22,293	$ 16,317
Deferred tax expense before reclassification	1,210	6,008
Deferred tax expense, reclassification from AOCI	$ 160	$ 1,338