Fair Value of Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Estimated Fair Value Of Financial Instruments [Line Items]
Fair value of Long-Term Debt	$ 660.7
7.75% Senior Notes [Member]
Estimated Fair Value Of Financial Instruments [Line Items]
Interest rate on Senior Notes	7.75%
7.375% Senior Notes [Member]
Estimated Fair Value Of Financial Instruments [Line Items]
Interest rate on Senior Notes	7.375%

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

Reference 1: 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

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