Mortgage Banking Activities, Loans Sold With Recourse (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Liability For Mortgage Loan Repurchase Losses [Abstract]
Carrying amount of residential mortgage loans sold and subject to repurchase agreement	$ 227,000,000	$ 259,000,000
Percentage of loans sold with recourse and either more than 90 days past due or in bankruptcy or foreclosure (in hundredths)	5.00%
Principal balance of loans sold with recourse and either 90 days or more past due or in bankruptcy or foreclosure	12,000,000
Percentage of loans sold with recourse and 30 to 89 days past due (in hundredths)	5.00%
Principal balance of loans sold with recourse and 30 to 89 days past due	12,000,000
Activity in the accrual for losses on loans sold with recourse [Roll forward]
Accrual for Losses on Mortgage Loans Sold With Recourse, Beginning balance	18,683,000	16,667,000	13,781,000
Provision for recourse losses	(1,891,000)	8,611,000	7,895,000
Loans charged off, net	(5,433,000)	(6,595,000)	(5,009,000)
Accrual for Losses on Mortgage Loans Sold With Recourse, Ending balance	11,359,000	18,683,000	16,667,000
Loans Sold Under Repurchase Agreement [Abstract]
Number of mortgages purchased under repurchase agreement with government sponsored entities.	39
Purchase price of loans purchased under repurchase agreement with government sponsored entities	4,800,000
Losses incurred on actual repurchased loans from governmental sponsored entities with warranties	1,300,000
Number of loans for which indemification was paid	2
Losses on mortgage loans indemnified during period	86,000
Number of loans with unresolved deficiency requests	389	247
Principal balance of loans with unresolved deficiency requests	44,831,000	36,978,000
Unpaid principal balance of mortgage loans subject to indemnification under standard representations and warranties	1,233,000	870,000
Accrual for credit losses for loan repurchase under representations and warranties	$ 5,291,000	$ 2,216,000