Components of Long-Term Debt and Capital Lease Obligations (Parenthetical) (Detail)	Mar. 31, 2013
6 3/4 % Senior Notes Due 2020
Long-Term Debt And Capital Lease Obligations [Line Items]
Interest percentage	6.75%
Debt maturity period	2020
6.0% Senior Notes Due 2022
Long-Term Debt And Capital Lease Obligations [Line Items]
Interest percentage	6.00%
Debt maturity period	2022

Interest rate stated in the contractual debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-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 210.5-02.22(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