Acquisition - Summary of Cash Purchase Price Allocated Based on Independent Appraisals and Managements Estimates (Detail) (USD $) In Thousands, unless otherwise specified				3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012 Robart Transportation Inc [Member]
Consideration:
Cash				$ (7,934)
Contingent consideration arrangement				(1,162)
Fair value of total consideration transferred				(9,096)
Acquisition related costs included in SG&A				150
Recognized amounts of identifiable assets acquired and liabilities assumed:
Current assets				2,082
Property and equipment				44
Customer lists				3,184
Current liabilities				(1,445)
Total identifiable net assets assumed				3,865
Goodwill	5,231	5,231		5,231
Total				$ 9,096