Derivatives and Hedging Activities (Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Position) (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]
Amount of (loss) gain recognized in accumulated other comprehensive income on interest rate derivatives (effective portion)	$ 14,920	$ (2,372)	$ 13,624	$ 15,682
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss reclassified from accumulated other comprehensive income into income as interest expense (ineffective portion)	$ (6,452)	$ (1,263)	$ (9,403)	$ (3,218)