Changes in Carrying Value of Goodwill (Details) $ in Thousands	3 Months Ended
	Nov. 30, 2017 USD ($)
Goodwill [Roll Forward]
Balance as of August 31, 2016	$ 530,081
Impact of changes in foreign currency rates	1,373
Balance as of November 30, 2017	531,454
Industrial
Goodwill [Roll Forward]
Balance as of August 31, 2016	103,875
Impact of changes in foreign currency rates	65
Balance as of November 30, 2017	103,940
Energy
Goodwill [Roll Forward]
Balance as of August 31, 2016	188,830
Impact of changes in foreign currency rates	1,925
Balance as of November 30, 2017	190,755
Engineered Solutions
Goodwill [Roll Forward]
Balance as of August 31, 2016	237,376
Impact of changes in foreign currency rates	(617)
Balance as of November 30, 2017	$ 236,759