Derivatives - Summary of Notional Amount, Effective Dates and Maturity Dates (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended
	Sep. 30, 2013	Feb. 28, 2011	Feb. 03, 2011
Forward Starting Interest Rate Swap, One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount	$ 75,000		$ 75,000
Effective Date	Aug. 01, 2013	Mar. 01, 2012
Maturity	Aug. 01, 2014	Sep. 01, 2012
Forward starting interest rate swap, Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount	75,000		75,000
Effective Date	Aug. 01, 2014	Sep. 04, 2012
Maturity	Aug. 03, 2015	Sep. 01, 2013
Forward starting interest rate swap, Three [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount	75,000		75,000
Effective Date	Aug. 03, 2015	Sep. 03, 2013
Maturity	Aug. 01, 2016	Sep. 01, 2014
Forward starting interest rate swap, Four [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount	75,000		75,000
Effective Date	Aug. 01, 2016	Sep. 02, 2014
Maturity	Aug. 01, 2017	Sep. 01, 2015
Forward starting interest rate swap, Five [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount			$ 75,000
Effective Date		Sep. 01, 2015
Maturity		Mar. 01, 2017