SUPPLEMENTAL GUARANTOR AND NON-GUARANTOR CONSOLIDATED FINANCIAL STATEMENTS - Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Condensed consolidating statements of comprehensive income (loss)
Net income	$ 319,564	$ 444,081	$ 600,801
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(1,324)	17,846	(18,932)
Unrealized gain (loss) on derivative instruments and other, net of zero tax	9,096	26,744	(35,417)
Comprehensive income	327,336	488,671	546,452
Eliminations
Condensed consolidating statements of comprehensive income (loss)
Net income	(112,531)	(476,533)	(1,646,867)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(147,756)	37,707	(398,464)
Unrealized gain (loss) on derivative instruments and other, net of zero tax	(13,915)	(41,932)	69,186
Comprehensive income	(274,202)	(480,758)	(1,976,145)
Parent | Reportable legal entities
Condensed consolidating statements of comprehensive income (loss)
Net income	319,564	444,081	600,801
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(1,324)	17,846	(18,932)
Unrealized gain (loss) on derivative instruments and other, net of zero tax	9,096	26,744	(35,417)
Comprehensive income	327,336	488,671	546,452
Guarantor Subsidiaries | Reportable legal entities
Condensed consolidating statements of comprehensive income (loss)
Net income	(151,290)	80,784	900,770
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	103,335	(21,972)	177,046
Unrealized gain (loss) on derivative instruments and other, net of zero tax	4,819	15,188	(33,769)
Comprehensive income	(43,136)	74,000	1,044,047
Non-Guarantor Subsidiaries | Reportable legal entities
Condensed consolidating statements of comprehensive income (loss)
Net income	263,821	395,749	746,097
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	44,421	(15,735)	221,418
Unrealized gain (loss) on derivative instruments and other, net of zero tax	9,096	26,744	(35,417)
Comprehensive income	$ 317,338	$ 406,758	$ 932,098