Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	$ 51,346	$ 60,519	$ 58,884	$ 67,915
Additions (deductions) [Abstract]
Provision for loan losses	251	6,171	6,438	21,029
Recoveries credited to allowance	1,372	898	4,603	3,080
Loans charged against the allowance	(5,119)	(8,768)	(21,294)	(33,204)
Reclassification to loans held for sale	171		(610)
Balance at end of period	48,021	58,820	48,021	58,820
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	23,059		23,059		22,299
Collectively evaluated for impairment	24,962		24,962		36,585
Total ending allowance balance	48,021		48,021		58,884
Loans [Abstract]
Individually evaluated for impairment	161,796		161,796		159,930
Collectively evaluated for impairment	1,275,291		1,275,291		1,422,509
Total loans recorded investment	1,437,087		1,437,087		1,582,439
Accrued interest included in recorded investment	5,098		5,098		5,831
Total loans	1,431,989		1,431,989		1,576,608
Commercial [Member]
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	15,476	17,697	18,183	23,836
Additions (deductions) [Abstract]
Provision for loan losses	18	3,335	2,708	9,378
Recoveries credited to allowance	782	229	2,178	960
Loans charged against the allowance	(2,619)	(4,330)	(9,242)	(17,243)
Reclassification to loans held for sale	16		(154)
Balance at end of period	13,673	16,931	13,673	16,931
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	8,368		8,368		10,252
Collectively evaluated for impairment	5,305		5,305		7,931
Total ending allowance balance	13,673		13,673		18,183
Loans [Abstract]
Individually evaluated for impairment	63,711		63,711		58,674
Collectively evaluated for impairment	541,588		541,588		594,665
Total loans recorded investment	605,299		605,299		653,339
Accrued interest included in recorded investment	1,761		1,761		2,184
Total loans	603,538		603,538		651,155
Mortgage [Member]
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	21,271	23,152	22,885	22,642
Additions (deductions) [Abstract]
Provision for loan losses	1,839	2,642	6,644	10,975
Recoveries credited to allowance	303	247	1,423	987
Loans charged against the allowance	(1,720)	(3,254)	(9,067)	(11,817)
Reclassification to loans held for sale	136		(56)
Balance at end of period	21,829	22,787	21,829	22,787
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	13,094		13,094		10,285
Collectively evaluated for impairment	8,735		8,735		12,600
Total ending allowance balance	21,829		21,829		22,885
Loans [Abstract]
Individually evaluated for impairment	90,580		90,580		93,702
Collectively evaluated for impairment	449,084		449,084		499,919
Total loans recorded investment	539,664		539,664		593,621
Accrued interest included in recorded investment	2,557		2,557		2,745
Total loans	537,107		537,107		590,876
Installment [Member]
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	4,981	6,289	6,146	6,769
Additions (deductions) [Abstract]
Provision for loan losses	(849)	693	(331)	2,374
Recoveries credited to allowance	287	421	1,002	1,128
Loans charged against the allowance	(793)	(1,131)	(2,973)	(3,999)
Reclassification to loans held for sale	133		(85)
Balance at end of period	3,759	6,272	3,759	6,272
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	1,597		1,597		1,762
Collectively evaluated for impairment	2,162		2,162		4,384
Total ending allowance balance	3,759		3,759		6,146
Loans [Abstract]
Individually evaluated for impairment	7,505		7,505		7,554
Collectively evaluated for impairment	191,011		191,011		212,907
Total loans recorded investment	198,516		198,516		220,461
Accrued interest included in recorded investment	780		780		902
Total loans	197,736		197,736		219,559
Payment Plan Receivable [Member]
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	195	346	197	389
Additions (deductions) [Abstract]
Provision for loan losses	(17)	6	6	51
Recoveries credited to allowance	0	1	0	5
Loans charged against the allowance	13	(53)	(12)	(145)
Reclassification to loans held for sale	0		0
Balance at end of period	191	300	191	300
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	191		191		197
Total ending allowance balance	191		191		197
Loans [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	93,608		93,608		115,018
Total loans recorded investment	93,608		93,608		115,018
Accrued interest included in recorded investment	0		0		0
Total loans	93,608		93,608		115,018
Unallocated [Member]
Analysis of allowance for loan losses by portfolio segment [Roll Forward]
Balance at beginning of period	9,423	13,035	11,473	14,279
Additions (deductions) [Abstract]
Provision for loan losses	(740)	(505)	(2,589)	(1,749)
Recoveries credited to allowance	0	0	0	0
Loans charged against the allowance	0	0	0	0
Reclassification to loans held for sale	(114)		(315)
Balance at end of period	8,569	12,530	8,569	12,530
Allowance for loan losses: [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	8,569		8,569		11,473
Total ending allowance balance	$ 8,569		$ 8,569		$ 11,473