Allowance for Loan Losses - Allowance for Loan Loss Activity by Class (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 10,138	$ 9,916	$ 9,916
Charge offs	327	190	1,721
Recoveries	56	118	343
Provision for loan losses	500	375	1,600
Ending balance	10,367	10,219	10,138
Ending balance specifically evaluated for impairment	768	599	974
Ending balance collectively evaluated for impairment	9,599	9,620	9,164
Total	1,089,735	1,004,942	1,071,526
Ending balance specifically evaluated for impairment	27,852	28,610	27,583
Ending balance collectively evaluated for impairment	1,061,883	976,332	1,043,943
Commercial \| Real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,988	3,120	3,120
Charge offs	164	0	294
Recoveries	0	0	0
Provision for loan losses	191	404	1,162
Ending balance	4,015	3,524	3,988
Ending balance specifically evaluated for impairment	351	69	505
Ending balance collectively evaluated for impairment	3,664	3,455	3,483
Total	304,663	279,683	302,506
Ending balance specifically evaluated for impairment	10,671	10,510	10,021
Ending balance collectively evaluated for impairment	293,992	269,173	292,485
Commercial \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	396	580	580
Charge offs	0	58	75
Recoveries	0	0	8
Provision for loan losses	45	(177)	(117)
Ending balance	441	345	396
Ending balance specifically evaluated for impairment	101	96	100
Ending balance collectively evaluated for impairment	340	249	296
Total	28,775	20,138	25,406
Ending balance specifically evaluated for impairment	763	967	763
Ending balance collectively evaluated for impairment	28,012	19,171	24,643
Commercial \| Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,780	1,452	1,452
Charge offs	0	0	376
Recoveries	11	20	129
Provision for loan losses	134	204	575
Ending balance	1,925	1,676	1,780
Ending balance specifically evaluated for impairment	39	21	39
Ending balance collectively evaluated for impairment	1,886	1,655	1,741
Total	158,507	133,629	150,769
Ending balance specifically evaluated for impairment	1,710	1,185	1,743
Ending balance collectively evaluated for impairment	156,797	132,444	149,026
Municipal
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	18	17	17
Charge offs	0	0	0
Recoveries	0	0	0
Provision for loan losses	0	0	1
Ending balance	18	17	18
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	18	17	18
Total	28,327	19,042	27,056
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	28,327	19,042	27,056
Residential \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	44	24	24
Charge offs	0	0	0
Recoveries	0	0	0
Provision for loan losses	(20)	9	20
Ending balance	24	33	44
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	24	33	44
Total	13,717	11,754	18,303
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	13,717	11,754	18,303
Residential \| Term
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,288	1,391	1,391
Charge offs	53	20	379
Recoveries	14	65	93
Provision for loan losses	(280)	38	183
Ending balance	969	1,474	1,288
Ending balance specifically evaluated for impairment	251	384	304
Ending balance collectively evaluated for impairment	718	1,090	984
Total	421,202	405,495	411,469
Ending balance specifically evaluated for impairment	13,260	14,540	13,669
Ending balance collectively evaluated for impairment	407,942	390,955	397,800
Home equity line of credit
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	807	893	893
Charge offs	7	49	147
Recoveries	0	1	5
Provision for loan losses	11	60	56
Ending balance	811	905	807
Ending balance specifically evaluated for impairment	26	29	26
Ending balance collectively evaluated for impairment	785	876	781
Total	110,016	110,249	110,907
Ending balance specifically evaluated for impairment	1,448	1,408	1,387
Ending balance collectively evaluated for impairment	108,568	108,841	109,520
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	559	566	566
Charge offs	103	63	450
Recoveries	31	32	108
Provision for loan losses	86	119	335
Ending balance	573	654	559
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	573	654	559
Total	24,528	24,952	25,110
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	24,528	24,952	25,110
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,258	1,873	1,873
Charge offs	0	0	0
Recoveries	0	0	0
Provision for loan losses	333	(282)	(615)
Ending balance	1,591	1,591	1,258
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	1,591	1,591	1,258
Total	0	0	0
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	$ 0	$ 0	$ 0

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

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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- Definition

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.

+ References

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- Definition

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

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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

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