Allowance For Loan Losses, Allowance For Losses On Lending-Related Commitments And Impaired Loans (Summary Of Loans Restructured And Subsequently Defaulted Under The Restructured Terms) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013 Loan		Mar. 31, 2012 Loan
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	58	[1],[2]	139	[1],[2]
Restructured loans	$ 35,106	[1],[2]	$ 130,851	[1],[2]
Count	14	[1],[3]	24,000	[1],[3]
Balance	14,557	[1],[3]	14,524	[1],[3]
Residential Real Estate And Other [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	10	[1],[2]	19	[1],[2]
Restructured loans	969	[1],[2]	6,777	[1],[2]
Count	2	[1],[3]	3,000	[1],[3]
Balance	221	[1],[3]	721	[1],[3]
Commercial And Industrial [Member] | Commercial Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	21	[1],[2]	20	[1],[2]
Restructured loans	14,901	[1],[2]	5,388	[1],[2]
Count	6	[1],[3]	6,000	[1],[3]
Balance	10,377	[1],[3]	664	[1],[3]
Residential Construction [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	3	[1],[2]	1	[1],[2]
Restructured loans	2,147	[1],[2]	1,105	[1],[2]
Count	0	[1],[3]	0	[1],[3]
Balance	0	[1],[3]	0	[1],[3]
Commercial Real Estate Construction Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	0	[1],[2]	10	[1],[2]
Restructured loans	0	[1],[2]	12,762	[1],[2]
Count	0	[1],[3]	1,000	[1],[3]
Balance	0	[1],[3]	467	[1],[3]
Land [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	5	[1],[2]	20	[1],[2]
Restructured loans	4,131	[1],[2]	34,452	[1],[2]
Count	1	[1],[3]	2,000	[1],[3]
Balance	651	[1],[3]	1,430	[1],[3]
Office [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	0	[1],[2]	6	[1],[2]
Restructured loans	0	[1],[2]	6,401	[1],[2]
Count	0	[1],[3]	2,000	[1],[3]
Balance	0	[1],[3]	421	[1],[3]
Industrial [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	1	[1],[2]	3	[1],[2]
Restructured loans	727	[1],[2]	2,110	[1],[2]
Count	0	[1],[3]	0	[1],[3]
Balance	0	[1],[3]	0	[1],[3]
Retail Site [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	4	[1],[2]	19	[1],[2]
Restructured loans	5,085	[1],[2]	27,746	[1],[2]
Count	0	[1],[3]	3,000	[1],[3]
Balance	0	[1],[3]	4,299	[1],[3]
Multi Family [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	2	[1],[2]	6	[1],[2]
Restructured loans	1,085	[1],[2]	4,414	[1],[2]
Count	1	[1],[3]	0	[1],[3]
Balance	705	[1],[3]	0	[1],[3]
Mixed Use And Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Troubled debt restructuring modifications, number of count	12	[1],[2]	35	[1],[2]
Restructured loans	6,061	[1],[2]	29,696	[1],[2]
Count	4	[1],[3]	7,000	[1],[3]
Balance	$ 2,603	[1],[3]	$ 6,522	[1],[3]

[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 considered to be in payment default are over 30 days past-due subsequent to the restructuring.