Loans and the Allowance for Loan Losses (Age Analysis of Past Due Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans and the Allowance for Loan Losses [Line Items]
Total past due	$ 1,248	$ 535
Non-accrual loans	4,626	6,922
Current loans	1,973,035	1,042,241
Total loans	1,978,909	1,049,698
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	874	438
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	161	97
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	213	0
Commercial real estate - owner occupied [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Non-accrual loans	1,066	0
Current loans	466,016	250,440
Total loans	467,082	250,440
Commercial real estate - owner occupied [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Commercial real estate - owner occupied [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Commercial real estate - owner occupied [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Commercial real estate - non-owner occupied [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Non-accrual loans	0	0
Current loans	436,083	184,688
Total loans	436,083	184,688
Commercial real estate - non-owner occupied [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Commercial real estate - non-owner occupied [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Commercial real estate - non-owner occupied [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Residential real estate [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	1,008	97
Non-accrual loans	0	431
Current loans	488,661	203,885
Total loans	489,669	204,413
Residential real estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	655	0
Residential real estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	140	97
Residential real estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	213	0
Commercial [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	157	438
Non-accrual loans	2,513	5,551
Current loans	460,982	305,497
Total loans	463,652	311,486
Commercial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	138	438
Commercial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	19	0
Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Real estate construction [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Non-accrual loans	865	940
Current loans	96,616	90,882
Total loans	97,481	91,822
Real estate construction [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Real estate construction [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Real estate construction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	0	0
Consumer [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	83	0
Non-accrual loans	182	0
Current loans	24,677	6,849
Total loans	24,942	6,849
Consumer [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	81	0
Consumer [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	2	0
Consumer [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans and the Allowance for Loan Losses [Line Items]
Total past due	$ 0	$ 0