Loans - Loan Modifications by Concession Type (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) loan	Sep. 30, 2016 USD ($) loan	Sep. 30, 2017 USD ($) loan	Sep. 30, 2016 USD ($) loan
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 2,926	$ 4,249	$ 6,608	$ 15,365
Total number of loans (in loan) | loan	38	6	73	61
Pre-modification recorded investment	$ 3,071	$ 4,249	$ 6,864	$ 15,365
Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	780	4,160	1,993	13,318
Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	479	89	2,247	297
Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	1,667	0	2,368	1,750
Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 2,558	$ 4,160	$ 5,548	$ 14,582
Total number of loans (in loan) | loan	19	4	37	38
Pre-modification recorded investment	$ 2,627	$ 4,160	$ 5,646	$ 14,582
Commercial loan portfolio | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	541	4,160	1,323	12,832
Commercial loan portfolio | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	350	0	1,857	0
Commercial loan portfolio | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	1,667	0	2,368	1,750
Commercial loan portfolio | Commercial
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 2,119	$ 4,160	$ 4,400	$ 12,141
Total number of loans (in loan) | loan	14	4	26	32
Pre-modification recorded investment	$ 2,173	$ 4,160	$ 4,476	$ 12,141
Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	506	4,160	841	10,391
Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	281	0	1,648	0
Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	1,332	0	1,911	1,750
Commercial loan portfolio | Commercial real estate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 404		$ 1,113	$ 2,441
Total number of loans (in loan) | loan	4		10	6
Pre-modification recorded investment	$ 418		$ 1,134	$ 2,441
Commercial loan portfolio | Commercial real estate | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0		447	2,441
Commercial loan portfolio | Commercial real estate | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	69		209	0
Commercial loan portfolio | Commercial real estate | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	335		457	0
Commercial loan portfolio | Real estate construction and land development
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 35		$ 35
Total number of loans (in loan) | loan	1		1
Pre-modification recorded investment	$ 36		$ 36
Commercial loan portfolio | Real estate construction and land development | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	35		35
Commercial loan portfolio | Real estate construction and land development | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0		0
Commercial loan portfolio | Real estate construction and land development | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0		0
Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 368	$ 89	$ 1,060	$ 783
Total number of loans (in loan) | loan	19	2	36	23
Pre-modification recorded investment	$ 444	$ 89	$ 1,218	$ 783
Consumer loan portfolio | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	239	0	670	486
Consumer loan portfolio | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	129	89	390	297
Consumer loan portfolio | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Residential mortgage
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 198		$ 594	$ 279
Total number of loans (in loan) | loan	3		9	3
Pre-modification recorded investment	$ 262		$ 676	$ 279
Consumer loan portfolio | Residential mortgage | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	76		211	279
Consumer loan portfolio | Residential mortgage | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	122		383	0
Consumer loan portfolio | Residential mortgage | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0		0	0
Consumer loan portfolio | Consumer installment
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 54		$ 86	$ 80
Total number of loans (in loan) | loan	11		17	12
Pre-modification recorded investment	$ 58		$ 93	$ 80
Consumer loan portfolio | Consumer installment | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	47		79	80
Consumer loan portfolio | Consumer installment | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	7		7	0
Consumer loan portfolio | Consumer installment | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0		0	0
Consumer loan portfolio | Home equity
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 116	$ 89	$ 380	$ 424
Total number of loans (in loan) | loan	5	2	10	8
Pre-modification recorded investment	$ 124	$ 89	$ 449	$ 424
Consumer loan portfolio | Home equity | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	116	0	380	127
Consumer loan portfolio | Home equity | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	89	0	297
Consumer loan portfolio | Home equity | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 0	$ 0	$ 0	$ 0