Shareholders' Equity - AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	$ 369,774
Net current period other comprehensive (loss) income	(18,991)	$ (5,780)	$ (10,012)
Shareholders' Equity Attributable to Parent, Ending Balance	457,015	369,774
Income tax benefit	2,548	1,565
Disproportionate tax effect	14,700
Deferred taxes provided for basis difference in foreign subsidiaries	0
Accumulated Other Comprehensive Loss, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	(88,126)	(83,007)	(72,954)
Other comprehensive loss before reclassification	(47,579)	(39,350)	(45,512)
Amounts reclassified from accumulated other comprehensive loss, net	28,570	34,231	35,459
Net current period other comprehensive (loss) income	(19,009)	(5,119)	(10,053)
Shareholders' Equity Attributable to Parent, Ending Balance	(107,135)	(88,126)	(83,007)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	(45,886)	(34,709)	(18,436)
Other comprehensive loss before reclassification	(34,999)	(11,177)	(16,273)
Net current period other comprehensive (loss) income	(34,999)	(11,177)	(16,273)
Shareholders' Equity Attributable to Parent, Ending Balance	(80,885)	(45,886)	(34,709)
Deferred income tax expense (benefit)	(4,113)	(1,565)
Deferred tax expense (benefit) before reclassification	(2,548)
Unrealized (losses) gains on interest rate swap contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' Equity Attributable to Parent, Beginning Balance	(42,240)	(48,298)	(54,518)
Other comprehensive loss before reclassification	(12,580)	(28,173)	(29,239)
Amounts reclassified from accumulated other comprehensive loss, net	28,570	34,231	35,459
Net current period other comprehensive (loss) income	15,990	6,058	6,220
Shareholders' Equity Attributable to Parent, Ending Balance	(26,250)	(42,240)	(48,298)
Deferred income tax expense (benefit)	9,269	(2,959)	(6,701)	$ (10,829)
Deferred tax expense (benefit) before reclassification	(9,619)	(17,402)	(19,405)
Deferred tax expense (benefit), reclassification from AOCI	$ 21,847	$ 21,143	$ 23,533