Debt - Effect of Derivative Instruments (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
Derivative Instruments, Gain (Loss) [Line Items]
Net other comprehensive gain (loss)	$ 2,311	$ (1,450)	$ (3,642)	$ 1,075
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in AOCI (effective portion)	2,761	(1,421)	(2,367)	1,158
Loss reclassified from AOCI into income (effective portion)	(450)	(29)	(1,275)	(83)
Net other comprehensive gain (loss)	$ 2,311	$ (1,450)	$ (3,642)	$ 1,075