Principal Changes in the Consolidated Statement of Operations as a Result of the Recasting for Retrospective Adjustments (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Sep. 30, 2010 As recasted	Jun. 30, 2010 As recasted	Sep. 30, 2010 As reported	Jun. 30, 2010 As reported	Sep. 30, 2010 Difference/Change	Jun. 30, 2010 Difference/Change
Business Acquisition [Line Items]
Net interest income	$ 374,542	$ 314,595	$ 717,901	$ 583,512	$ 356,778	$ 314,595	$ 386,918	$ 278,976	$ (30,140)	$ 35,619
Provision for loan losses					215,013	202,258	215,013	202,258
Net interest (expense) income after provision for loan losses	230,225	112,337	498,265	141,054	141,765	112,337	171,905	76,718	(30,140)	35,619
Non-interest income	124,160	198,827	288,528	356,693	825,894	198,827	796,524	215,858	29,370	(17,031)
Operating expenses	281,800	328,416	556,849	609,329	371,541	328,416	371,547	328,416	(6)
Income (loss) before income tax	72,585	(17,252)	229,944	(111,582)	596,118	(17,252)	596,882	(35,840)	(764)	18,588
Income tax expense	(38,100)	27,237	109,127	17,962	102,032	27,237	102,388	19,988	(356)	7,249
Net (loss) income	$ 110,685	$ (44,489)	$ 120,817	$ (129,544)	$ 494,086	$ (44,489)	$ 494,494	$ (55,828)	$ (408)	$ 11,339