USE OF DERIVATIVE FINANCIAL INSTRUMENTS, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Changes in AOCI (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	$ 247,265		$ 293,910
Other comprehensive income (loss) before reclassifications	(38,406)		(94,901)
Amounts reclassified from accumulated other comprehensive income	3,698	4,835	13,548	14,630
Net other comprehensive income (loss)	(34,708)	63,291	(81,353)	123,674
Ending Balance	212,557		212,557
Gains and Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(2,686)		(32,539)
Other comprehensive income (loss) before reclassifications	(10,867)		9,136
Amounts reclassified from accumulated other comprehensive income	3,698		13,548
Net other comprehensive income (loss)	(7,169)		22,684
Ending Balance	(9,855)		(9,855)
Unrealized Gains and Losses on Available-for-sale Securities [Member]
Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	249,951		326,449
Other comprehensive income (loss) before reclassifications	(27,539)		(104,037)
Amounts reclassified from accumulated other comprehensive income	0		0
Net other comprehensive income (loss)	(27,539)		(104,037)
Ending Balance	$ 222,412		$ 222,412