Allowance for Loan Losses - Summary of Allowance for Loan Losses and Recorded Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 576	$ 77
Allowance for Loan Losses, Collectively Evaluated for Impairment	58,470	56,313
Total Allowance for Loan Losses	59,046	56,390	$ 55,816	$ 52,775
Portfolio Loans, Individually Evaluated for Impairment	29,892	26,823
Portfolio Loans, Collectively Evaluated for Impairment	5,700,721	5,734,626
Total Portfolio Loans	5,730,613	5,761,449
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0	0
Allowance for Loan Losses, Collectively Evaluated for Impairment	30,963	27,235
Total Allowance for Loan Losses	30,963	27,235	20,570	19,976
Portfolio Loans, Individually Evaluated for Impairment	3,774	3,546
Portfolio Loans, Collectively Evaluated for Impairment	2,757,117	2,682,448
Total Portfolio Loans	2,760,891	2,685,994
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	537	29
Allowance for Loan Losses, Collectively Evaluated for Impairment	9,935	8,937
Total Allowance for Loan Losses	10,472	8,966	13,244	10,810
Portfolio Loans, Individually Evaluated for Impairment	12,573	7,284
Portfolio Loans, Collectively Evaluated for Impairment	1,394,377	1,425,982
Total Portfolio Loans	1,406,950	1,433,266
Commercial construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0	0
Allowance for Loan Losses, Collectively Evaluated for Impairment	10,721	13,167
Total Allowance for Loan Losses	10,721	13,167	14,102	13,999
Portfolio Loans, Individually Evaluated for Impairment	3,444	5,464
Portfolio Loans, Collectively Evaluated for Impairment	320,697	378,870
Total Portfolio Loans	324,141	384,334
Consumer real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0	21
Allowance for Loan Losses, Collectively Evaluated for Impairment	5,418	5,458
Total Allowance for Loan Losses	5,418	5,479	5,956	6,095
Portfolio Loans, Individually Evaluated for Impairment	10,052	10,488
Portfolio Loans, Collectively Evaluated for Impairment	1,161,689	1,180,163
Total Portfolio Loans	1,171,741	1,190,651
Other consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	39	27
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,433	1,516
Total Allowance for Loan Losses	1,472	1,543	$ 1,944	$ 1,895
Portfolio Loans, Individually Evaluated for Impairment	49	41
Portfolio Loans, Collectively Evaluated for Impairment	66,841	67,163
Total Portfolio Loans	$ 66,890	$ 67,204

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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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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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