Debt Facilities - Summary of Senior Notes (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Senior notes	$ 2,250,000	$ 2,250,000
5.375% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Senior notes	1,000,000	1,000,000
7.00% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Senior notes	750,000	750,000
4.875% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Senior notes	$ 500,000	$ 500,000

Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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)

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

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