Acquisitions (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 22, 2015	Aug. 31, 2016	Aug. 31, 2015	Jul. 20, 2015	Aug. 31, 2014
Business Acquisition [Line Items]
Acquisition related costs			$ 1,800
Weighted average useful life in years		11 years 6 months
Goodwill		$ 76,803	$ 76,801		$ 37,021
Tradenames [Member]
Business Acquisition [Line Items]
Indefinite-lived intangible assets acquired		$ 7,430
Elecsys [Member]
Business Acquisition [Line Items]
Business Acquisition, Share Price	$ 17.50
Finite-lived intangible assets acquired	$ 17,100
Total cash consideration	70,577
Total cash consideration, net of cash acquired	67,176
Business acquisition allocation, cash	3,401
Goodwill	$ 39,986
SPF Water Engineering [Member]
Business Acquisition [Line Items]
Total cash consideration				$ 2,500
Total cash consideration, net of cash acquired				2,400
Business acquisition allocation, cash				100
Current assets				700
Fixed assets				100
Finite-lived intangible assets				1,000
Goodwill				900
Current liabilities				$ 200