Variable Interest Entities - Schedule of Carrying Value of Assets and Liabilities of PEAKS Trust (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Feb. 28, 2013	Dec. 31, 2012	Jun. 30, 2012
Variable Interest Entity [Line Items]
Allowance for Loan losses	$ 0	$ 0	$ 0	$ 0
Excluding current portion, less allowance for loan losses	4,319		0	0
PEAKS Trust Student Loans [Member]
Variable Interest Entity [Line Items]
Allowance for Loan losses	0	0
Excluding current portion, less allowance for loan losses	$ 4,319	$ 0

A valuation allowance relating to a written agreement to receive money (at a specified future date(s) within one year from the reporting date (or the normal operating cycle, whichever is longer), consisting of principal as well as any accrued interest) for the portion that is expected to be uncollectible.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.4)

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

Name:	us-gaap_AllowanceForNotesAndLoansReceivableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant