Intangible Assets, Goodwill and Acquisitions - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 855,430	$ 831,415
Accumulated Amortization	(550,143)	(460,144)
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	624,530	600,515
Accumulated Amortization	(322,702)	(275,993)
Trademarks
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	230,900	230,900
Accumulated Amortization	$ (227,441)	$ (184,151)