Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income	$ 15,157	$ 20,114	$ 14,263	$ 35,473
Unrealized gain (loss) on interest rate swap contracts, net of deferred income tax expense (benefit) of $535 and $(2,222) for the three months ended June 30, 2017 and 2016, respectively; and $1,895 and $(8,112) for the six months ended June 30, 2017 and 2016, respectively	4,184	(9,337)	5,589	(20,023)
Foreign currency translation adjustments, net of deferred income tax expense (benefit) of $72 and $(1,166) for the three months ended June 30, 2017 and 2016, respectively; and $(1,311) and $(1,991) for the six months ended June 30, 2017 and 2016, respectively	26,025	(14,670)	33,271	(19,941)
Other comprehensive income (loss)	30,209	(24,007)	38,860	(39,964)
Total comprehensive income (loss)	45,366	(3,893)	53,123	(4,491)
Less: comprehensive (loss) income attributable to noncontrolling interests	(1)	(196)	5	(101)
Comprehensive income (loss) attributable to controlling interests	$ 45,367	$ (3,697)	$ 53,118	$ (4,390)