Accumulated Other Comprehensive Income (Change in AOCI, Net of Tax) (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	$ 1,900,758	$ 1,963,380
Other comprehensive (loss) income before reclassifications	1,589
Amounts reclassified from AOCI	6,883
Total other comprehensive income (loss)	8,472	(12,549)
Ending Balance	1,849,293	1,905,513
Foreign Currency Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(14,298)
Other comprehensive (loss) income before reclassifications	(529)
Amounts reclassified from AOCI	0
Total other comprehensive income (loss)	(529)
Ending Balance	(14,827)
Derivative Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(39,398)
Derivative Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive (loss) income before reclassifications	10,945
Amounts reclassified from AOCI	6,883
Total other comprehensive income (loss)	17,828
Ending Balance	(21,570)
Actuarial Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(28,033)
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified from AOCI	0
Total other comprehensive income (loss)	0
Ending Balance	(28,033)
Prior Service Cost
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(608)
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified from AOCI	0
Total other comprehensive income (loss)	0
Ending Balance	(608)
Available for Sale Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(457)
Other comprehensive (loss) income before reclassifications	(8,827)
Amounts reclassified from AOCI	0
Total other comprehensive income (loss)	(8,827)
Ending Balance	(9,284)
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(82,794)	(19,399)
Total other comprehensive income (loss)	8,472	(12,549)
Ending Balance	$ (74,322)	$ (31,948)