Allowance For Loan Losses, Allowance For Losses On Lending-Related Commitments And Impaired Loans (Summary Of The Post-Modification Balance Of Loans Restructured) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013 Loan		Mar. 31, 2012 Loan
Troubled debt restructuring modifications, number of count	58	[1],[2]	139	[1],[2]
Restructured loans	$ 35,106	[1],[2]	$ 130,851	[1],[2]
Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	10	[1],[2]	19	[1],[2]
Restructured loans	969	[1],[2]	6,777	[1],[2]
Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	21	[1],[2]	20	[1],[2]
Restructured loans	14,901	[1],[2]	5,388	[1],[2]
Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1],[2]	10	[1],[2]
Restructured loans	0	[1],[2]	12,762	[1],[2]
Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	5	[1],[2]	20	[1],[2]
Restructured loans	4,131	[1],[2]	34,452	[1],[2]
Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	4	[1],[2]	19	[1],[2]
Restructured loans	5,085	[1],[2]	27,746	[1],[2]
Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	2	[1],[2]	6	[1],[2]
Restructured loans	1,085	[1],[2]	4,414	[1],[2]
Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	12	[1],[2]	35	[1],[2]
Restructured loans	6,061	[1],[2]	29,696	[1],[2]
All Modifications [Member]
Troubled debt restructuring modifications, number of count	14	[1],[3]	31	[1],[3]
Restructured loans	2,277	[1],[3]	39,683	[1],[3]
All Modifications [Member] | Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	4	[1],[3]	4	[1],[3]
Restructured loans	377	[1],[3]	1,046	[1],[3]
All Modifications [Member] | Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	6	[1],[3]	3	[1],[3]
Restructured loans	708	[1],[3]	118	[1],[3]
All Modifications [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1],[3]	2	[1],[3]
Restructured loans	0	[1],[3]	622	[1],[3]
All Modifications [Member] | Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	2	[1],[3]	14	[1],[3]
Restructured loans	287	[1],[3]	27,992	[1],[3]
All Modifications [Member] | Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1],[3]	5	[1],[3]
Restructured loans	200	[1],[3]	8,633	[1],[3]
All Modifications [Member] | Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1],[3]	0	[1],[3]
Restructured loans	705	[1],[3]	0	[1],[3]
All Modifications [Member] | Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1],[3]	3	[1],[3]
Restructured loans	0	[1],[3]	1,272	[1],[3]
Extension At Below Market Terms [Member]
Troubled debt restructuring modifications, number of count	11	[1]	28	[1]
Restructured loans	1,835	[1]	39,460	[1]
Extension At Below Market Terms [Member] | Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	2	[1]	3	[1]
Restructured loans	70	[1]	927	[1]
Extension At Below Market Terms [Member] | Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	5	[1]	1	[1]
Restructured loans	573	[1]	14	[1]
Extension At Below Market Terms [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	2	[1]
Restructured loans	0	[1]	622	[1]
Extension At Below Market Terms [Member] | Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	2	[1]	14	[1]
Restructured loans	287	[1]	27,992	[1]
Extension At Below Market Terms [Member] | Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1]	5	[1]
Restructured loans	200	[1]	8,633	[1]
Extension At Below Market Terms [Member] | Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1]	0	[1]
Restructured loans	705	[1]	0	[1]
Extension At Below Market Terms [Member] | Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	3	[1]
Restructured loans	0	[1]	1,272	[1]
Reduction Of Interest Rate [Member]
Troubled debt restructuring modifications, number of count	11	[1]	22	[1]
Restructured loans	2,106	[1]	37,589	[1]
Reduction Of Interest Rate [Member] | Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	3	[1]	1	[1]
Restructured loans	361	[1]	118	[1]
Reduction Of Interest Rate [Member] | Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	4	[1]	0	[1]
Restructured loans	553	[1]	0	[1]
Reduction Of Interest Rate [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	2	[1]
Restructured loans	0	[1]	622	[1]
Reduction Of Interest Rate [Member] | Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	2	[1]	12	[1]
Restructured loans	287	[1]	27,004	[1]
Reduction Of Interest Rate [Member] | Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1]	5	[1]
Restructured loans	200	[1]	8,633	[1]
Reduction Of Interest Rate [Member] | Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1]	0	[1]
Restructured loans	705	[1]	0	[1]
Reduction Of Interest Rate [Member] | Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	2	[1]
Restructured loans	0	[1]	1,212	[1]
Modification To Interest Only Payments [Member]
Troubled debt restructuring modifications, number of count	3	[1]	23	[1]
Restructured loans	308	[1]	33,897	[1]
Modification To Interest Only Payments [Member] | Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	1	[1]	2	[1]
Restructured loans	123	[1]	844	[1]
Modification To Interest Only Payments [Member] | Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	2	[1]	2	[1]
Restructured loans	185	[1]	104	[1]
Modification To Interest Only Payments [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	2	[1]
Restructured loans	0	[1]	622	[1]
Modification To Interest Only Payments [Member] | Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	11	[1]
Restructured loans	0	[1]	22,954	[1]
Modification To Interest Only Payments [Member] | Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	4	[1]
Restructured loans	0	[1]	8,244	[1]
Modification To Interest Only Payments [Member] | Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Modification To Interest Only Payments [Member] | Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	2	[1]
Restructured loans	0	[1]	1,129	[1]
Forgiveness Of Debt [Member]
Troubled debt restructuring modifications, number of count	1	[1]	0	[1]
Restructured loans	73	[1]	0	[1]
Forgiveness Of Debt [Member] | Residential Real Estate And Other [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Forgiveness Of Debt [Member] | Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Forgiveness Of Debt [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Forgiveness Of Debt [Member] | Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	1	[1]	0	[1]
Restructured loans	73	[1]	0	[1]
Forgiveness Of Debt [Member] | Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Forgiveness Of Debt [Member] | Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	0	[1]	0	[1]
Forgiveness Of Debt [Member] | Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled debt restructuring modifications, number of count	0	[1]	0	[1]
Restructured loans	$ 0	[1]	$ 0	[1]

[1] Balances represent the recorded investment in the loan at the time of the restructuring.

[2] Total restructured loans represent all loans restructured during the previous twelve months from the date indicated.

[3] Restructured loans may have more than one modification representing a concession. As such, restructured loans during the period may be represented in more than one of the categories noted above.