Stockholders' Equity (Comprehensive Income) (Details) - USD ($) $ in Thousands	8 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Apr. 24, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, start		$ 1,706,909	$ 1,811,462
Total other comprehensive income (loss)	$ (50,827)	113,800	(14,259)	$ (3,856)
Balance, end	1,811,462	1,815,314	1,706,909
Change in unrealized gain (loss) on derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, start		3,619	888
Other comprehensive income (loss) before reclassifications, before tax		(9,861)	2,959
Tax benefit (expense)		2,653	(795)
Other comprehensive income (loss) before reclassifications, net of tax		(7,208)	2,164
Reclassification of loss from accumulated other comprehensive income, before tax		3,448	971
Tax effect		(778)	(404)
Reclassification of loss from accumulated other comprehensive income, after tax		(2,670)	(567)
Total other comprehensive income (loss)		(4,538)	2,731
Balance, end	888	(919)	3,619
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, start		(72,106)	(55,116)
Other comprehensive income (loss) before reclassifications, before tax		118,338	(16,990)
Tax benefit (expense)		0	0
Other comprehensive income (loss) before reclassifications, net of tax		118,338	(16,990)
Reclassification of loss from accumulated other comprehensive income, before tax		0	0
Tax effect		0	0
Reclassification of loss from accumulated other comprehensive income, after tax		0	0
Total other comprehensive income (loss)		118,338	(16,990)
Balance, end	(55,116)	46,232	(72,106)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, start		(68,487)	(54,228)
Other comprehensive income (loss) before reclassifications, before tax		108,477	(14,031)
Tax benefit (expense)		2,653	(795)
Other comprehensive income (loss) before reclassifications, net of tax		111,130	(14,826)
Reclassification of loss from accumulated other comprehensive income, before tax		3,448	971
Tax effect		(778)	(404)
Reclassification of loss from accumulated other comprehensive income, after tax		(2,670)	(567)
Total other comprehensive income (loss)		113,800	(14,259)
Balance, end	$ (54,228)	$ 45,313	$ (68,487)