Loans and Allowance for Loan Losses (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Impaired loans disaggregated by class
Recorded Investment	$ 76,160	$ 62,300
Unpaid Principal Balance	114,664	88,585
Related Allowance	11,199	7,567
Average Recorded Investment	79,365	86,178
Interest Income Recognized	235	678
With No Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	10,361	29,633
Unpaid Principal Balance	24,738	49,494
Related Allowance
Average Recorded Investment	18,346	21,395
Interest Income Recognized	24	417
With Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	65,799	32,667
Unpaid Principal Balance	89,926	39,091
Related Allowance	11,199	7,567
Average Recorded Investment	61,019	64,783
Interest Income Recognized	211	261
Commercial Loans [Member]
Impaired loans disaggregated by class
Recorded Investment	65,933	56,420
Unpaid Principal Balance	100,854	80,195
Related Allowance	10,634	6,997
Average Recorded Investment	71,132	78,185
Interest Income Recognized	203	613
Commercial Loans [Member] | With No Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	8,821	28,051
Unpaid Principal Balance	21,651	46,692
Related Allowance
Average Recorded Investment	16,030	18,461
Interest Income Recognized	24	359
Commercial Loans [Member] | With Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	57,112	28,369
Unpaid Principal Balance	79,203	33,503
Related Allowance	10,634	6,997
Average Recorded Investment	55,102	59,724
Interest Income Recognized	179	254
Residential mortgage Loans [Member]
Impaired loans disaggregated by class
Recorded Investment	10,227	5,880
Unpaid Principal Balance	13,810	8,390
Related Allowance	565	570
Average Recorded Investment	8,233	7,993
Interest Income Recognized	32	65
Residential mortgage Loans [Member] | With No Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	1,540	1,582
Unpaid Principal Balance	3,087	2,802
Related Allowance
Average Recorded Investment	2,316	2,934
Interest Income Recognized		58
Residential mortgage Loans [Member] | With Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment	8,687	4,298
Unpaid Principal Balance	10,723	5,588
Related Allowance	565	570
Average Recorded Investment	5,917	5,059
Interest Income Recognized	32	7
Consumer loan [Member]
Impaired loans disaggregated by class
Recorded Investment
Unpaid Principal Balance
Related Allowance
Average Recorded Investment
Interest Income Recognized
Consumer loan [Member] | With No Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment
Unpaid Principal Balance
Related Allowance
Average Recorded Investment
Interest Income Recognized
Consumer loan [Member] | With Related Allowance Recorded [Member]
Impaired loans disaggregated by class
Recorded Investment
Unpaid Principal Balance
Related Allowance
Average Recorded Investment
Interest Income Recognized