Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Nov. 30, 2015	Aug. 31, 2015	Nov. 30, 2014	Aug. 31, 2014	Nov. 30, 2015	Nov. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (20,004)	$ (8,471)	$ 26,818	$ 28,428	$ (8,471)	$ 28,428
Other comprehensive loss before reclassifications	(4,636)	(12,021)	(9,796)	(2,098)
Amounts reclassified from accumulated other comprehensive income (loss)	6,960	488	488	488
Other comprehensive income (loss)	2,324	(11,533)	(9,308)	(1,610)	(9,209)	(10,918)
Ending Balance	(17,680)	(20,004)	17,510	26,818	(17,680)	17,510
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(9,026)	2,987	39,410	41,525	2,987	41,525
Other comprehensive loss before reclassifications	(4,626)	(12,013)	(9,778)	(2,115)
Amounts reclassified from accumulated other comprehensive income (loss)	6,472	0	0	0
Other comprehensive income (loss)	1,846	(12,013)	(9,778)	(2,115)
Ending Balance	(7,180)	(9,026)	29,632	39,410	(7,180)	29,632
Unrealized Loss on Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(10,138)	(10,626)	(12,110)	(12,615)	(10,626)	(12,615)
Other comprehensive loss before reclassifications		0	(21)	17
Amounts reclassified from accumulated other comprehensive income (loss)	488	488	488	488
Other comprehensive income (loss)	488	488	467	505
Ending Balance	(9,650)	(10,138)	(11,643)	(12,110)	(9,650)	(11,643)
Other
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(840)	(832)	(482)	(482)	(832)	(482)
Other comprehensive loss before reclassifications	(10)	(8)	3	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss)	(10)	(8)	3	0
Ending Balance	$ (850)	$ (840)	$ (479)	$ (482)	$ (850)	$ (479)