Fair Value Measurements - Schedule of Liabilities Measured at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Liabilities:
Long-term obligations	$ 1,890,759
Derivative financial instruments	1,548
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Liabilities:
Long-term obligations
Derivative financial instruments
Significant Other Observable Inputs (Level 2) [Member]
Liabilities:
Long-term obligations	1,470,546
Derivative financial instruments	1,548
Significant Unobservable Inputs (Level 3) [Member]
Liabilities:
Long-term obligations	420,213
Derivative financial instruments

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 15

-Paragraph 83

-URI http://asc.fasb.org/extlink&oid=6913464&loc=d3e34841-113949

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 10

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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