Loans Receivable - Schedule of Troubled Debt Restructurings (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Loans Receivable [Line Items]
Accruing Loans, Current	$ 2,123	$ 676
Accruing Loans, Past Due Greater than 30 Days	207
Nonaccrual TDRs	16,178	26,663
Total TDRs	18,508	27,339
Residential Mortgage Loans [Member] | Mortgage - Prime [Member]
Loans Receivable [Line Items]
Accruing Loans, Current
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs
Total TDRs
Commercial Loans [Member] | Real Estate [Member]
Loans Receivable [Line Items]
Accruing Loans, Current	843	650
Accruing Loans, Past Due Greater than 30 Days	207
Nonaccrual TDRs	15,677	24,477
Total TDRs	16,727	25,127
Commercial Loans [Member] | Business [Member]
Loans Receivable [Line Items]
Accruing Loans, Current	1,188	26
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs	281	1,957
Total TDRs	1,469	1,983
Consumer And Other Loans [Member] | Indirect Automobile [Member]
Loans Receivable [Line Items]
Accruing Loans, Current
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs
Total TDRs
Consumer And Other Loans [Member] | Home Equity [Member]
Loans Receivable [Line Items]
Accruing Loans, Current	92
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs	220	229
Total TDRs	312	229
Consumer And Other Loans [Member] | Credit Card [Member]
Loans Receivable [Line Items]
Accruing Loans, Current
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs
Total TDRs
Consumer And Other Loans [Member] | Other [Member]
Loans Receivable [Line Items]
Accruing Loans, Current
Accruing Loans, Past Due Greater than 30 Days
Nonaccrual TDRs
Total TDRs