Restricted Cash - Schedule of Restricted Cash (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 48,369	$ 39,697
Restricted Cash - Current Asset [Member] \| Securitization Escrow Accounts [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	35,439	26,774
Restricted Cash - Current Asset [Member] \| Payment and Performance Bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	939	934
Other Assets - Noncurrent [Member] \| Surety Bonds and Workers Compensation [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 11,991	$ 11,989

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-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 210.5-02.1)

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

Name:	us-gaap_RestrictedCashAndCashEquivalents
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant