Allowance for Loan Losses and Reserve for Unfunded Loan Commitments - Loans and their Related Allowance for Loan Losses, by Portfolio Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 667	$ 332
Collectively evaluated for impairment	14,821	13,224
Total	15,488	13,556	$ 12,579	$ 12,759
Individually evaluated for impairment	3,292	1,459
Collectively evaluated for impairment	1,290,103	1,146,405
Total	1,293,395	1,147,864
SBA loans held for investment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	540	194
Collectively evaluated for impairment	1,115	1,277
Total	1,655	1,471	1,576	1,961
Individually evaluated for impairment	1,471	605
Collectively evaluated for impairment	37,862	43,394
Total	39,333	43,999
SBA 504 loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	29,155	21,871
Commercial loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	127	138
Collectively evaluated for impairment	8,578	7,687
Total	8,705	7,825	7,302	7,050
Individually evaluated for impairment	1,821	854
Collectively evaluated for impairment	692,281	628,011
Total	694,102	628,865
Residential mortgage loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,900	3,130
Total	3,900	3,130	2,593	2,769
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	436,056	365,145
Total	436,056	365,145
Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,228	1,130
Total	1,228	1,130	925	817
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	123,904	109,855
Total	123,904	109,855
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	$ 0	$ 0	$ 183	$ 162

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.

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

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