CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Statement of Comprehensive Income [Abstract]
Income taxes, unrealized holding gain (loss) on derivatives	$ (55)	$ 110	$ (1,178)	$ (434)
Income taxes, reclassification for loss (gain) on derivatives included in net earnings	469	(50)	886	258
Income taxes, net unrealized loss on derivatives	414	60	(292)	(176)
Income taxes, net gain of defined benefit obligation	0	0	4	296
Income taxes, amortization of prior services of defined benefit obligation	(1)	(1)	(2)	(2)
Income taxes, defined benefit obligation	$ (1)	$ (1)	$ 2	$ 294