Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Subsequent Events - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Oct. 31, 2013 Tractor	Jan. 31, 2014 Subsequent Event [Member]	Jan. 31, 2014 Minimum [Member] Subsequent Event [Member]	Jan. 31, 2014 Maximum [Member] Subsequent Event [Member]
Subsequent Event [Line Items]
Purchase contract units, tractors	200
Total costs of purchasing tractors	$ 25.4
Secured debt period		5 years
Interest on secured debt			1.87%	1.93%