Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 4) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Financing Receivable, Impaired
Recorded Investment	$ 150,937,000	$ 145,488,000	$ 148,734,000
Unpaid Contractual Principal Balance	200,856,000	213,698,000	194,517,000
Related Allowance	14,118,000	8,655,000	13,262,000
Average Recorded Investment	149,839,000	167,694,000
Interest Income Recognized	185,000	617,000
Nonaccrual loans included in impaired loans	104,441,000		101,873,000
Troubled debt restructured loans on accrual	46,111,000		46,647,000
Deferred fees, accrued interest and premiums and discounts, net	385,000		214,000
Nonaccrual loans under $500,000 that are not individually evaluated for impairment	8,400,000		10,200,000
TDR loans	88,100,000		89,400,000
Specific Reserves	4,500,000		1,700,000
Total Troubled Debt Restructured Loans
Financing Receivable, Impaired
Number of Contracts	7
Pre-Modification Outstanding Principal	23,169,000
Period-End Outstanding Principal	23,090,000
Troubled debt restructured loans that have subsequently defaulted
Number of contracts	3
Period-End Outstanding Principal	6,365,000
Period-End Specific Reserve	3,328,000
Commercial
Financing Receivable, Impaired
Recorded Investment	40,415,000	13,323,000	25,780,000
Unpaid Contractual Principal Balance	53,712,000	32,035,000	32,965,000
Related Allowance	3,335,000	2,291,000	7,135,000
Average Recorded Investment	33,098,000	14,593,000
Number of Contracts	5
Pre-Modification Outstanding Principal	16,982,000
Period-End Outstanding Principal	16,903,000
Troubled debt restructured loans that have subsequently defaulted
Number of contracts	1
Period-End Outstanding Principal	26,000
Period-End Specific Reserve	10,000
Commercial real estate mortgages
Financing Receivable, Impaired
Recorded Investment	22,306,000	25,790,000	30,678,000
Unpaid Contractual Principal Balance	27,737,000	32,433,000	35,198,000
Related Allowance	1,019,000	1,060,000	1,551,000
Average Recorded Investment	26,493,000	34,213,000
Interest Income Recognized	69,000	130,000
Residential mortgage
Financing Receivable, Impaired
Recorded Investment	13,000,000	12,476,000	9,146,000
Unpaid Contractual Principal Balance	14,277,000	13,661,000	10,046,000
Related Allowance	331,000	384,000	108,000
Average Recorded Investment	11,074,000	14,733,000
Interest Income Recognized		155,000
Fixed
Financing Receivable, Impaired
Number of Contracts	1
Pre-Modification Outstanding Principal	655,000
Period-End Outstanding Principal	655,000
Real estate construction
Financing Receivable, Impaired
Recorded Investment	67,686,000	81,604,000	75,811,000
Unpaid Contractual Principal Balance	96,033,000	117,075,000	102,321,000
Related Allowance	9,395,000	334,000	4,377,000
Average Recorded Investment	71,749,000	94,982,000
Interest Income Recognized	116,000	230,000
Construction
Financing Receivable, Impaired
Number of Contracts	1
Pre-Modification Outstanding Principal	5,532,000
Period-End Outstanding Principal	5,532,000
Land
Troubled debt restructured loans that have subsequently defaulted
Number of contracts	2
Period-End Outstanding Principal	6,339,000
Period-End Specific Reserve	3,318,000
Equity lines of credit
Financing Receivable, Impaired
Recorded Investment	6,980,000	4,249,000	6,633,000
Unpaid Contractual Principal Balance	8,170,000	4,793,000	7,786,000
Related Allowance	38,000	72,000	91,000
Average Recorded Investment	6,807,000	4,561,000
Interest Income Recognized		3,000
Installment loan
Financing Receivable, Impaired
Recorded Investment	550,000	6,938,000	658,000
Unpaid Contractual Principal Balance	927,000	7,458,000	976,000
Related Allowance		4,514,000
Average Recorded Investment	604,000	4,058,000
Lease financing
Financing Receivable, Impaired
Recorded Investment		1,108,000	28,000
Unpaid Contractual Principal Balance		6,243,000	5,225,000
Average Recorded Investment	14,000	554,000
Interest Income Recognized		99,000
Impaired loans without specific allowance
Financing Receivable, Impaired
Recorded Investment	102,783,000	111,627,000	99,655,000
Unpaid Contractual Principal Balance	135,358,000	168,570,000	129,072,000
Average Recorded Investment	101,221,000	130,552,000
Interest Income Recognized	185,000	614,000
Impaired loans without specific allowance | Commercial
Financing Receivable, Impaired
Recorded Investment	27,822,000	6,400,000	10,153,000
Unpaid Contractual Principal Balance	36,069,000	15,721,000	11,588,000
Average Recorded Investment	18,988,000	6,848,000
Impaired loans without specific allowance | Commercial real estate mortgages
Financing Receivable, Impaired
Recorded Investment	14,008,000	18,491,000	19,867,000
Unpaid Contractual Principal Balance	19,022,000	24,047,000	23,983,000
Average Recorded Investment	16,938,000	20,994,000
Interest Income Recognized	69,000	130,000
Impaired loans without specific allowance | Residential mortgage
Financing Receivable, Impaired
Recorded Investment	9,233,000	9,509,000	7,182,000
Unpaid Contractual Principal Balance	10,434,000	10,604,000	8,035,000
Average Recorded Investment	8,208,000	12,249,000
Interest Income Recognized		155,000
Impaired loans without specific allowance | Fixed
Financing Receivable, Impaired
Recorded Investment	2,666,000	6,238,000	3,493,000
Unpaid Contractual Principal Balance	3,194,000	7,324,000	4,035,000
Average Recorded Investment	3,080,000	8,590,000
Interest Income Recognized		145,000
Impaired loans without specific allowance | Variable
Financing Receivable, Impaired
Recorded Investment	6,567,000	3,271,000	3,689,000
Unpaid Contractual Principal Balance	7,240,000	3,280,000	4,000,000
Average Recorded Investment	5,128,000	3,659,000
Interest Income Recognized		10,000
Impaired loans without specific allowance | Real estate construction
Financing Receivable, Impaired
Recorded Investment	45,135,000	72,786,000	56,426,000
Unpaid Contractual Principal Balance	61,721,000	108,084,000	72,940,000
Average Recorded Investment	50,781,000	86,148,000
Interest Income Recognized	116,000	230,000
Impaired loans without specific allowance | Construction
Financing Receivable, Impaired
Recorded Investment	21,045,000	49,258,000	27,435,000
Unpaid Contractual Principal Balance	34,381,000	83,788,000	40,605,000
Average Recorded Investment	24,240,000	62,518,000
Interest Income Recognized	116,000	230,000
Impaired loans without specific allowance | Land
Financing Receivable, Impaired
Recorded Investment	24,090,000	23,528,000	28,991,000
Unpaid Contractual Principal Balance	27,340,000	24,296,000	32,335,000
Average Recorded Investment	26,541,000	23,630,000
Impaired loans without specific allowance | Equity lines of credit
Financing Receivable, Impaired
Recorded Investment	6,035,000	3,292,000	5,341,000
Unpaid Contractual Principal Balance	7,185,000	3,830,000	6,325,000
Average Recorded Investment	5,688,000	3,149,000
Impaired loans without specific allowance | Installment loan
Financing Receivable, Impaired
Recorded Investment	550,000	41,000	658,000
Unpaid Contractual Principal Balance	927,000	41,000	976,000
Average Recorded Investment	604,000	610,000
Impaired loans without specific allowance | Commercial Installment loan
Financing Receivable, Impaired
Average Recorded Investment		569,000
Impaired loans without specific allowance | Consumer Installment loan
Financing Receivable, Impaired
Recorded Investment	550,000	41,000	658,000
Unpaid Contractual Principal Balance	927,000	41,000	976,000
Average Recorded Investment	604,000	41,000
Impaired loans without specific allowance | Lease financing
Financing Receivable, Impaired
Recorded Investment		1,108,000	28,000
Unpaid Contractual Principal Balance		6,243,000	5,225,000
Average Recorded Investment	14,000	554,000
Interest Income Recognized		99,000
Impaired loans with a specific allowance
Financing Receivable, Impaired
Recorded Investment	48,154,000	33,861,000	49,079,000
Unpaid Contractual Principal Balance	65,498,000	45,128,000	65,445,000
Related Allowance	14,118,000	8,655,000	13,262,000
Average Recorded Investment	48,618,000	37,142,000
Interest Income Recognized		3,000
Impaired loans with a specific allowance | Commercial
Financing Receivable, Impaired
Recorded Investment	12,593,000	6,923,000	15,627,000
Unpaid Contractual Principal Balance	17,643,000	16,314,000	21,377,000
Related Allowance	3,335,000	2,291,000	7,135,000
Average Recorded Investment	14,110,000	7,745,000
Impaired loans with a specific allowance | Commercial real estate mortgages
Financing Receivable, Impaired
Recorded Investment	8,298,000	7,299,000	10,811,000
Unpaid Contractual Principal Balance	8,715,000	8,386,000	11,215,000
Related Allowance	1,019,000	1,060,000	1,551,000
Average Recorded Investment	9,555,000	13,219,000
Impaired loans with a specific allowance | Residential mortgage
Financing Receivable, Impaired
Recorded Investment	3,767,000	2,967,000	1,964,000
Unpaid Contractual Principal Balance	3,843,000	3,057,000	2,011,000
Related Allowance	331,000	384,000	108,000
Average Recorded Investment	2,866,000	2,484,000
Impaired loans with a specific allowance | Fixed
Financing Receivable, Impaired
Recorded Investment	2,341,000	1,553,000	515,000
Unpaid Contractual Principal Balance	2,367,000	1,549,000	535,000
Related Allowance	287,000	103,000	40,000
Average Recorded Investment	1,428,000	1,060,000
Impaired loans with a specific allowance | Variable
Financing Receivable, Impaired
Recorded Investment	1,426,000	1,414,000	1,449,000
Unpaid Contractual Principal Balance	1,476,000	1,508,000	1,476,000
Related Allowance	44,000	281,000	68,000
Average Recorded Investment	1,438,000	1,424,000
Impaired loans with a specific allowance | Real estate construction
Financing Receivable, Impaired
Recorded Investment	22,551,000	8,818,000	19,385,000
Unpaid Contractual Principal Balance	34,312,000	8,991,000	29,381,000
Related Allowance	9,395,000	334,000	4,377,000
Average Recorded Investment	20,968,000	8,834,000
Impaired loans with a specific allowance | Construction
Financing Receivable, Impaired
Recorded Investment		8,818,000
Unpaid Contractual Principal Balance		8,991,000
Related Allowance		334,000
Average Recorded Investment		8,834,000
Impaired loans with a specific allowance | Land
Financing Receivable, Impaired
Recorded Investment	22,551,000		19,385,000
Unpaid Contractual Principal Balance	34,312,000		29,381,000
Related Allowance	9,395,000		4,377,000
Average Recorded Investment	20,968,000
Impaired loans with a specific allowance | Equity lines of credit
Financing Receivable, Impaired
Recorded Investment	945,000	957,000	1,292,000
Unpaid Contractual Principal Balance	985,000	963,000	1,461,000
Related Allowance	38,000	72,000	91,000
Average Recorded Investment	1,119,000	1,412,000
Interest Income Recognized		3,000
Impaired loans with a specific allowance | Installment loan
Financing Receivable, Impaired
Recorded Investment		6,897,000
Unpaid Contractual Principal Balance		7,417,000
Related Allowance		4,514,000
Average Recorded Investment		3,448,000
Impaired loans with a specific allowance | Commercial Installment loan
Financing Receivable, Impaired
Recorded Investment		6,897,000
Unpaid Contractual Principal Balance		7,417,000
Related Allowance		4,514,000
Average Recorded Investment		$ 3,448,000