Goodwill and Other Identifiable Intangible Assets, Net (Goodwill Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning balance	$ 131,995	$ 109,448
Acquisitions	17,341	2,737
Foreign currency translation adjustment	(3)	(1,069)
Ending balance	$ 149,333	$ 111,116