Loans (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	$ 1,874,010	$ 1,868,550
Loans collectively evaluated for impairment	1,861,410	1,855,837
Loans individually evaluated for impairment	11,536	11,551
Loans acquired with deteriorated credit quality	1,064	1,162
Allowance for loan losses
Balance at the beginning of the period	24,920	28,522
Provision (credit)		(400)us-gaap_ProvisionForLoanAndLeaseLosses
Charge-offs	(214)	(4,244)
Recoveries	176	1,042
Balance at the end of the period	24,882	24,920
Allowance for loans collectively evaluated for impairment	23,745	23,544
Allowance for loans individually evaluated for impairment	1,137	1,376
Commercial and industrial
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	594,980	588,200
Loans collectively evaluated for impairment	587,861	580,889
Loans individually evaluated for impairment	7,041	7,239
Loans acquired with deteriorated credit quality	78	72
Allowance for loan losses
Balance at the beginning of the period	11,819	7,644
Provision (credit)	(24)	4,593
Charge-offs	(12)	(661)
Recoveries	7	243
Balance at the end of the period	11,790	11,819
Allowance for loans collectively evaluated for impairment	11,204	10,790
Allowance for loans individually evaluated for impairment	586	1,029
Construction and development excluding undeveloped land
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	99,846	95,733
Loans collectively evaluated for impairment	98,849	94,603
Loans individually evaluated for impairment	516	516
Loans acquired with deteriorated credit quality	481	614
Allowance for loan losses
Balance at the beginning of the period	721	2,555
Provision (credit)	74	(1,584)
Charge-offs		(250)
Balance at the end of the period	795	721
Allowance for loans collectively evaluated for impairment	705	706
Allowance for loans individually evaluated for impairment	90	15
Undeveloped land
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	19,995	21,268
Loans collectively evaluated for impairment	19,995	21,268
Allowance for loan losses
Balance at the beginning of the period	1,545	5,376
Provision (credit)	(398)	(2,244)
Charge-offs		(1,753)
Recoveries		166
Balance at the end of the period	1,147	1,545
Allowance for loans collectively evaluated for impairment	1,147	1,545
Real estate mortgage
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	1,129,941	1,133,953
Loans collectively evaluated for impairment	1,125,536	1,129,766
Loans individually evaluated for impairment	3,905	3,720
Loans acquired with deteriorated credit quality	500	467
Allowance for loan losses
Balance at the beginning of the period	10,541	12,604
Provision (credit)	378	(1,190)
Charge-offs	(63)	(993)
Recoveries	15	120
Balance at the end of the period	10,871	10,541
Allowance for loans collectively evaluated for impairment	10,484	10,285
Allowance for loans individually evaluated for impairment	387	256
Consumer
Balance in the recorded investment in loans and allowance for loan losses by portfolio segment and based on impairment method
Loans	29,248	29,396
Loans collectively evaluated for impairment	29,169	29,311
Loans individually evaluated for impairment	74	76
Loans acquired with deteriorated credit quality	5	9
Allowance for loan losses
Balance at the beginning of the period	294	343
Provision (credit)	(30)	25
Charge-offs	(139)	(587)
Recoveries	154	513
Balance at the end of the period	279	294
Allowance for loans collectively evaluated for impairment	205	218
Allowance for loans individually evaluated for impairment	$ 74	$ 76

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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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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