Guarantor Subsidiaries - Additional Information (Detail) (7.375% Senior Secured Notes [Member], USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
Jun. 30, 2012	Dec. 31, 2012	Apr. 30, 2012
7.375% Senior Secured Notes [Member]
Debt Instrument [Line Items]
Senior secure notes issued	$ 210,000
Senior secured note interest rate	7.375%		7.375%
Senior secured notes maturity date	May 15, 2019	May 15, 2019

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

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

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-Name Accounting Standards Codification

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

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

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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