Debt - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2014 Contract	Sep. 30, 2013	Sep. 30, 2014 Contract	Sep. 30, 2013
Debt Instrument [Line Items]
Number of interest rate swap contracts outstanding	7		7
Hedge ineffectiveness	$ 0	$ 0	$ 0	$ 0
Scenario Forecast [Member]
Debt Instrument [Line Items]
Hedge ineffectiveness	$ 0		$ 0

Amount of gain (loss) from the ineffectiveness of the hedge.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Name:	us-gaap_DerivativeNetHedgeIneffectivenessGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration