Acquisitions - Proforma Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013
Net sales
Net sales, As reported	$ 378,187	$ 344,205	$ 1,045,513	$ 952,482
Net sales, Pro forma	384,835	368,944	1,065,566	1,034,779
Earnings from continuing operations
Earnings from continuing operations, As reported	50,557	46,077	105,866	102,462
Earnings from continuing operations, Pro Forma	$ 50,931	$ 46,184	$ 106,647	$ 105,929
Basic earnings per share from continuing operations
Basic earnings per share from continuing operations, As reported (in dollars per share)	$ 0.72	$ 0.63	$ 1.47	$ 1.40
Basic earnings per share from continuing operations, Pro Forma (in dollars per share)	$ 0.72	$ 0.63	$ 1.48	$ 1.45
Diluted earnings per share from continuing operations
Diluted earnings per share from continuing operations, As reported (in dollars per share)	$ 0.70	$ 0.62	$ 1.44	$ 1.38
Diluted earnings per share from continuing operations, Pro Forma (in dollars per share)	$ 0.71	$ 0.62	$ 1.45	$ 1.42