Consolidated Statements Of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidated Statements Of Comprehensive (Loss) Income [Abstract]
Net (loss) income	$ (175,570)	$ 27,478	$ (161,307)	$ 62,951
Unrealized gain (loss) on interest rate swap contracts, net of deferred income tax expense (benefit) of $1,744 and $4,590 for the three months ended September 30, 2017 and 2016, respectively; and $3,639 and $(3,522) for the nine months ended September 30, 2017 and 2016, respectively	5,190	8,452	10,779	(11,571)
Foreign currency translation adjustments, net of deferred income tax expense (benefit) of $55 and $(564) for the three months ended September 30, 2017 and 2016, respectively; and $1,256 and $(2,555) for the nine months ended September 30, 2017 and 2016, respectively	17,871	(6,745)	51,142	(26,686)
Other comprehensive income (loss)	23,061	1,707	61,921	(38,257)
Total comprehensive (loss) income	(152,509)	29,185	(99,386)	24,694
Less: comprehensive (loss) income attributable to noncontrolling interests	(9)	198	(4)	97
Comprehensive (loss) income attributable to controlling interests	$ (152,500)	$ 28,987	$ (99,382)	$ 24,597