Loans (Details 10) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Balance at beginning of period	$ 87,785	$ 89,674	$ 88,333	$ 89,530
Provision for loan losses	4,000	7,000	9,000	14,500
Loan charge-offs	(6,172)	(8,306)	(12,719)	(16,948)
Loan recoveries	1,098	1,365	2,097	2,651
Balance at end of period	86,711	89,733	86,711	89,733
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	8,138	11,621	8,138	11,621	9,286
Loans collectively evaluated for impairment related to allowance for loan losses	76,373	78,112	76,373	78,112	77,447
Loans acquired with deteriorated credit quality related to allowance for loan losses	2,200		2,200		1,600
Total	86,711	89,733	86,711	89,733
Loans individually evaluated for impairment related to recorded investment (loan balance)	100,021	120,367	100,021	120,367	105,806
Loans collectively evaluated for impairment related to recorded investment (loan balance)	3,415,089	3,104,812	3,415,089	3,104,812	3,232,696
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	447,232	522,831	447,232	522,831	492,783
Total loans	3,962,342	3,748,010	3,962,342	3,748,010	3,831,285
Commercial Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Balance at beginning of period	54,917	57,526	55,645	59,443
Provision for loan losses	1,601	5,395	3,638	9,090
Loan charge-offs	(3,197)	(5,276)	(6,576)	(11,190)
Loan recoveries	438	927	1,052	1,229
Balance at end of period	53,759	58,572	53,759	58,572
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	7,461	10,876	7,461	10,876	8,582
Loans collectively evaluated for impairment related to allowance for loan losses	44,698	47,696	44,698	47,696	45,863
Loans acquired with deteriorated credit quality related to allowance for loan losses	1,600		1,600		1,200
Total	53,759	58,572	53,759	58,572
Loans individually evaluated for impairment related to recorded investment (loan balance)	81,622	98,211	81,622	98,211	80,794
Loans collectively evaluated for impairment related to recorded investment (loan balance)	1,661,425	1,506,869	1,661,425	1,506,869	1,582,379
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	386,187	445,281	386,187	445,281	422,152
Total loans	2,129,234	2,050,361	2,129,234	2,050,361	2,085,325
Consumer Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Balance at beginning of period	27,726	27,417	29,166	27,338
Provision for loan losses	4,373	4,458	5,716	6,281
Loan charge-offs	(2,975)	(3,030)	(6,143)	(5,758)
Loan recoveries	660	438	1,045	1,422
Balance at end of period	29,784	29,283	29,784	29,283
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	677	745	677	745	704
Loans collectively evaluated for impairment related to allowance for loan losses	28,507	28,538	28,507	28,538	28,062
Loans acquired with deteriorated credit quality related to allowance for loan losses	600		600		400
Total	29,784	29,283	29,784	29,283
Loans individually evaluated for impairment related to recorded investment (loan balance)	18,399	22,156	18,399	22,156	25,012
Loans collectively evaluated for impairment related to recorded investment (loan balance)	1,753,664	1,597,943	1,753,664	1,597,943	1,650,317
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	61,045	77,550	61,045	77,550	70,631
Total loans	1,833,108	1,697,649	1,833,108	1,697,649	1,745,960
Unallocated [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Balance at beginning of period	5,142	4,731	3,522	2,749
Provision for loan losses	(1,974)	(2,853)	354	(871)
Loan charge-offs
Loan recoveries
Balance at end of period	3,168	1,878	3,168	1,878
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses
Loans collectively evaluated for impairment related to allowance for loan losses	3,168	1,878	3,168	1,878	3,522
Loans acquired with deteriorated credit quality related to allowance for loan losses
Total	3,168	1,878	3,168	1,878
Loans individually evaluated for impairment related to recorded investment (loan balance)
Loans collectively evaluated for impairment related to recorded investment (loan balance)
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)
Total loans

The balance of financing receivables that were acquired with deteriorated credit quality.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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