Accumulated Other Comprehensive Income (Loss) - Changes in AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
AOCI, Net of Tax [Roll Forward]
Beginning Balance	$ 3,016,526	$ 2,302,793	$ 1,842,659
Other comprehensive income (loss) before reclassifications	(54,316)	20,305
Amounts reclassified from accumulated other comprehensive income (loss)	(1,179)	(933)
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(55,495)	19,372	21,845
Ending Balance	3,002,721	3,016,526	2,302,793
Foreign Currency
AOCI, Net of Tax [Roll Forward]
Beginning Balance	6,550	(12,726)
Other comprehensive income (loss) before reclassifications	(21,572)	19,276
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(21,572)	19,276
Ending Balance	(15,022)	6,550	(12,726)
Unrealized Income (Loss) on Interest Rate Hedges
AOCI, Net of Tax [Roll Forward]
Beginning Balance	10,449	11,382
Other comprehensive income (loss) before reclassifications	(27,659)	0
Amounts reclassified from accumulated other comprehensive income (loss)	(1,179)	(933)
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(28,838)	(933)
Ending Balance	(18,389)	10,449	11,382
Other
AOCI, Net of Tax [Roll Forward]
Beginning Balance	(656)	(1,685)
Other comprehensive income (loss) before reclassifications	(5,085)	1,029
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(5,085)	1,029
Ending Balance	(5,741)	(656)	(1,685)
Other Accumulated Comprehensive Income (Loss)
AOCI, Net of Tax [Roll Forward]
Beginning Balance	16,343	(3,029)	(24,874)
Ending Balance	$ (39,152)	$ 16,343	$ (3,029)