Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014 item	Sep. 30, 2013 item	Sep. 30, 2012 item
Acquisitions.
Number of business acquisitions	7	4	6
Aggregate assets acquired:
Goodwill	$ 23,622	$ 15,821	$ 14,752
Goodwill expected to be deductible for tax purposes	7,801	1,069	5,899
Trademarks, tradenames, customer relationships and non-compete agreement | Minimum
Aggregate assets acquired:
Amortization period	2 years
Trademarks, tradenames, customer relationships and non-compete agreement | Maximum
Aggregate assets acquired:
Amortization period	15 years
Acquisitions
ACQUISITIONS
Aggregate purchase price in cash	16,377	3,382	12,248
Aggregate assets acquired:
Current assets	2,773	794	3,213
Property, plant and equipment			178
Goodwill	7,801	1,069	5,899
Intangible assets	5,803	1,519	2,958
Aggregate purchase price	16,377	3,382	12,248
Acquired intangible assets expected to be deductible for tax purposes	$ 5,803	$ 1,519	$ 2,958
Expected period for deduction of acquired intangible assets for tax purposes	15 years
Expected period for deduction of acquired goodwill for tax purposes	15 years