Subsequent Events (Details) (Subsequent event, CNG-In-A-Box, USD $) In Thousands, unless otherwise specified	0 Months Ended
Jan. 23, 2014
Subsequent event \| CNG-In-A-Box
Subsequent events
Number of CNG-In-A-Box units purchased	67
Equipment purchased	$ 18,377

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentAdditions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration