Allowance for Loan Losses - Summary of Allowance for Loan Losses and Recorded Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 77	$ 798
Allowance for Loan Losses, Collectively Evaluated for Impairment	56,313	51,977
Total Allowance for Loan Losses	56,390	52,775	$ 48,147
Portfolio Loans, Individually Evaluated for Impairment	26,823	41,935
Portfolio Loans, Collectively Evaluated for Impairment	5,734,626	5,569,484
Total Portfolio Loans	5,761,449	5,611,419
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	27,235	19,976
Total Allowance for Loan Losses	27,235	19,976	15,043
Portfolio Loans, Individually Evaluated for Impairment	3,546	16,352
Portfolio Loans, Collectively Evaluated for Impairment	2,682,448	2,482,124
Total Portfolio Loans	2,685,994	2,498,476
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	29	771
Allowance for Loan Losses, Collectively Evaluated for Impairment	8,937	10,039
Total Allowance for Loan Losses	8,966	10,810	10,853
Portfolio Loans, Individually Evaluated for Impairment	7,284	6,866
Portfolio Loans, Collectively Evaluated for Impairment	1,425,982	1,394,169
Total Portfolio Loans	1,433,266	1,401,035
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	13,167	13,999
Total Allowance for Loan Losses	13,167	13,999	12,625
Portfolio Loans, Individually Evaluated for Impairment	5,464	6,613
Portfolio Loans, Collectively Evaluated for Impairment	378,870	449,271
Total Portfolio Loans	384,334	455,884
Consumer real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	21	26
Allowance for Loan Losses, Collectively Evaluated for Impairment	5,458	6,069
Total Allowance for Loan Losses	5,479	6,095	8,400
Portfolio Loans, Individually Evaluated for Impairment	10,488	12,079
Portfolio Loans, Collectively Evaluated for Impairment	1,180,163	1,178,093
Total Portfolio Loans	1,190,651	1,190,172
Other consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	27	1
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,516	1,894
Total Allowance for Loan Losses	1,543	1,895	$ 1,226
Portfolio Loans, Individually Evaluated for Impairment	41	25
Portfolio Loans, Collectively Evaluated for Impairment	67,163	65,827
Total Portfolio Loans	$ 67,204	$ 65,852

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

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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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