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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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

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

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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 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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Allowance for Loan Losses Allowance by Impairment Analysis Method (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	$ 22,577	$ 26,030
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	654	1,135
Financing Receivable, Collectively Evaluated for Impairment	6,482,451	6,088,324
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	74,088	76,942
Total loans	6,505,028	6,114,354
Loans and Leases Receivable, Allowance	74,742	78,077	$ 78,500	$ 75,838
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	939,690	1,009,974
Loans and Leases Receivable, Allowance			15,814	14,114
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	2,440,220	2,302,244
Loans and Leases Receivable, Allowance			44,215	43,854
Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	164,990	104,839
Loans and Leases Receivable, Allowance			6,322	4,041
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	2,682,533	2,379,861
Loans and Leases Receivable, Allowance			10,544	10,374
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	99,958	118,817
Loans and Leases Receivable, Allowance			1,085	1,003
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	177,637	198,619
Loans and Leases Receivable, Allowance			520	$ 382
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	125	0
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	125	0
Financing Receivable, Collectively Evaluated for Impairment	177,512	198,619
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	505	391
Total loans	177,637	198,619
Loans and Leases Receivable, Allowance	630	391	520
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	1,815	37
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	20	22
Financing Receivable, Collectively Evaluated for Impairment	98,143	118,780
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	815	1,013
Total loans	99,958	118,817
Loans and Leases Receivable, Allowance	835	1,035	1,085
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	10,165	12,418
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	89	565
Financing Receivable, Collectively Evaluated for Impairment	2,672,368	2,367,443
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	9,684	9,884
Total loans	2,682,533	2,379,861
Loans and Leases Receivable, Allowance	9,773	10,449	10,544
Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	109	179
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0
Financing Receivable, Collectively Evaluated for Impairment	164,881	104,660
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	4,949	3,039
Total loans	164,990	104,839
Loans and Leases Receivable, Allowance	4,949	3,039	6,322
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	8,687	11,603
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	362	548
Financing Receivable, Collectively Evaluated for Impairment	2,431,533	2,290,641
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	46,458	49,864
Total loans	2,440,220	2,302,244
Loans and Leases Receivable, Allowance	46,820	50,412	44,215
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Individually Evaluated for Impairment	1,676	1,793
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	58	0
Financing Receivable, Collectively Evaluated for Impairment	938,014	1,008,181
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	11,677	12,751
Total loans	939,690	1,009,974
Loans and Leases Receivable, Allowance	$ 11,735	$ 12,751	$ 15,814