Summary Of Derivative By Hedge Designation (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative [Line Items]
Realized loss reclassified from accumulated other comprehensive loss to interest expense			$ (3,707)	$ (9,841)
Realized loss reclassified to interest expense			3,707	9,841
Unrealized loss from changes in the fair value of the effective portion of the interest rate swaps			(9,676)	(7,952)
(Loss) gain included in other comprehensive income (loss)	$ (1,742)	$ (866)	$ (5,969)	$ 1,889