Risk Category of Loans by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	$ 118,790		$ 224,924
Total Unpaid Principal Balance	1,763,196		2,188,083
Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	770,943		1,074,816
Pass
Financing Receivable, Recorded Investment [Line Items]
Percent of total unpaid principal balance	74.30%		64.60%
Total Unpaid Principal Balance	1,519,665	[1]	1,740,542	[1]
Pass | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	21,141		20,693
Pass | Land and construction | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	64,229		68,175
Pass | Multi-family | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	245,980		278,936
Pass | Retail/office | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	156,919		208,159
Pass | Other consumer | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	107,465		143,225
Pass | Total
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	595,734		719,188
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Percent of total unpaid principal balance	4.20%		5.10%
Total Unpaid Principal Balance	33,363		56,762
Special Mention | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	878		255
Special Mention | Land and construction | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	787		6,344
Special Mention | Multi-family | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	3,660		2,728
Special Mention | Retail/office | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	5,144		13,080
Special Mention | Other consumer | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	22,894		34,355
Special Mention | Total
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	33,363		56,762
Substandard
Financing Receivable, Recorded Investment [Line Items]
Percent of total unpaid principal balance	11.40%		14.90%
Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	5,640		9,812
Substandard | Land and construction | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	15,150		47,300
Substandard | Multi-family | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	17,155		22,790
Substandard | Retail/office | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	19,100		43,221
Substandard | Other consumer | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	34,333		42,732
Substandard | Total
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	91,378		165,855
Total Unpaid Principal Balance Amount
Financing Receivable, Recorded Investment [Line Items]
Percent of total unpaid principal balance	100.00%		100.00%
Total Unpaid Principal Balance Amount | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	30,574		38,977
Total Unpaid Principal Balance Amount | Land and construction | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	111,953		186,048
Total Unpaid Principal Balance Amount | Multi-family | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	287,447		342,216
Total Unpaid Principal Balance Amount | Retail/office | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	198,686		298,277
Total Unpaid Principal Balance Amount | Other consumer | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	172,857		248,275
Total Unpaid Principal Balance Amount | Total
Financing Receivable, Recorded Investment [Line Items]
Total Unpaid Principal Balance	801,517		1,113,793
Non-Accrual
Financing Receivable, Recorded Investment [Line Items]
Percent of total unpaid principal balance	10.10%		15.40%
Non-Accrual	81,042		171,988
Total Unpaid Principal Balance	118,790		224,924
Non-Accrual | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	2,915		8,217
Non-Accrual | Land and construction | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	31,787		64,229
Non-Accrual | Multi-family | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	20,652		37,762
Non-Accrual | Retail/office | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	17,523		33,817
Non-Accrual | Other consumer | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	$ 8,165		$ 27,963

[1] Includes all accrual residential and consumer loans as these loans are not individually rated.