Goodwill and Intangible Assets - Components of Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Customer relationships and noncompete agreements	$ 519,103	$ 511,130
Trademarks and tradenames (not subject to amortization)	82,944	81,800
Gross carrying amount	602,047	592,930
Accumulated amortization	(137,709)	(99,281)
Intangible assets, net	$ 464,338	$ 493,649