Indebtedness - Senior Notes, Revolving Credit and Term Loan Agreement - Additional Information (Detail) - Current Credit Facility	1 Months Ended
May. 31, 2015 USD ($)
Debt [Line Items]
Credit facility expiration date	2019-06
Revolving credit facility	$ 900,000,000
Credit facility term	5 years
Revolving line of credit	$ 600,000,000
Term loan	$ 300,000,000

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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