Effect of Derivative Instruments on Consolidated Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in OCI on Derivative (Effective Portion)	$ (696)	$ (1,826)	$ (9,096)	$ 10,096
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	(2,589)	(3,621)	(9,399)	(12,098)
(Loss) Gain on Cash Flow Hedge Ineffectiveness, Net	(25)	(1)	(88)	26
Designated as Hedging Instrument [Member] | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	(2,589)	(3,621)	(9,399)	(12,098)
(Loss) Gain on Cash Flow Hedge Ineffectiveness, Net	(25)	(1)	(88)	26
Designated as Hedging Instrument [Member] | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in OCI on Derivative (Effective Portion)	(696)	(1,826)	(9,096)	10,096
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, (Loss) Gain Recognized in Income, Net	(10)	(5)	(138)	(8)
Not Designated as Hedging Instrument [Member] | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, (Loss) Gain Recognized in Income, Net	$ (10)	$ (5)	$ (138)	$ (8)