Loans and Allowance for Loan Losses - Impaired Loan Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Related Allowance	$ 465		$ 465		$ 631
Total impaired loans, Recorded Investment	4,725		4,725		4,173
Total impaired loans, Unpaid Principal Balance	5,230		5,230		4,570
Total impaired loans, Average Recorded Investment	4,797	$ 5,931	4,586	$ 5,141
Total impaired loans, Interest Income Recognized	60	9	82	42
All Other Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	1,273		1,273		1,356
Impaired loans without a valuation allowance, Unpaid Principal Balance	1,274		1,274		1,361
Impaired loans with a valuation allowance, Recorded Investment	1,233		1,233		1,154
Impaired loans with a valuation allowance, Unpaid Principal Balance	1,239		1,239		1,154
Impaired loans with a valuation allowance, Related Allowance	465		465		475
Impaired loans without a valuation allowance, Average Recorded Investment	1,282	1,728	1,306	1,937
Impaired loans without a valuation allowance, Interest Income Recognized	11	7	18	31
Impaired loans with a valuation allowance, Average Recorded Investment	1,381	575	1,304	786
Impaired loans with a valuation allowance, Interest Income Recognized	8	2	21	18
All Other Loans [Member] \| Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	553		553		256
Impaired loans without a valuation allowance, Unpaid Principal Balance	553		553		261
Impaired loans with a valuation allowance, Recorded Investment	396		396		0
Impaired loans with a valuation allowance, Unpaid Principal Balance	402		402		0
Impaired loans with a valuation allowance, Related Allowance	44		44		0
Impaired loans without a valuation allowance, Average Recorded Investment	345	424	315	495
Impaired loans without a valuation allowance, Interest Income Recognized	1	5	4	25
Impaired loans with a valuation allowance, Average Recorded Investment	396	24	264	16
Impaired loans with a valuation allowance, Interest Income Recognized	0	0	2	0
All Other Loans [Member] \| Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	720		720		553
Impaired loans without a valuation allowance, Unpaid Principal Balance	721		721		553
Impaired loans with a valuation allowance, Recorded Investment	680		680		994
Impaired loans with a valuation allowance, Unpaid Principal Balance	680		680		994
Impaired loans with a valuation allowance, Related Allowance	292		292		343
Impaired loans without a valuation allowance, Average Recorded Investment	633	624	606	774
Impaired loans without a valuation allowance, Interest Income Recognized	10	0	14	4
Impaired loans with a valuation allowance, Average Recorded Investment	827	217	882	199
Impaired loans with a valuation allowance, Interest Income Recognized	5	2	14	9
All Other Loans [Member] \| Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	0		0		547
Impaired loans without a valuation allowance, Unpaid Principal Balance	0		0		547
Impaired loans with a valuation allowance, Recorded Investment	0		0		0
Impaired loans with a valuation allowance, Unpaid Principal Balance	0		0		0
Impaired loans with a valuation allowance, Related Allowance	0		0		0
Impaired loans without a valuation allowance, Average Recorded Investment	304	650	385	616
Impaired loans without a valuation allowance, Interest Income Recognized	0	2	0	1
Impaired loans with a valuation allowance, Average Recorded Investment	0	28	0	19
Impaired loans with a valuation allowance, Interest Income Recognized	0	0	0	0
All Other Loans [Member] \| Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	0		0		0
Impaired loans without a valuation allowance, Unpaid Principal Balance	0		0		0
Impaired loans with a valuation allowance, Recorded Investment	157		157		160
Impaired loans with a valuation allowance, Unpaid Principal Balance	157		157		160
Impaired loans with a valuation allowance, Related Allowance	129		129		132
Impaired loans without a valuation allowance, Average Recorded Investment	0	16	0	33
Impaired loans without a valuation allowance, Interest Income Recognized	0	0	0	1
Impaired loans with a valuation allowance, Average Recorded Investment	158	293	158	514
Impaired loans with a valuation allowance, Interest Income Recognized	3	0	5	9
All Other Loans [Member] \| Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without a valuation allowance, Recorded Investment	0		0		0
Impaired loans without a valuation allowance, Unpaid Principal Balance	0		0		0
Impaired loans with a valuation allowance, Recorded Investment	0		0		0
Impaired loans with a valuation allowance, Unpaid Principal Balance	0		0		0
Impaired loans with a valuation allowance, Related Allowance	0		0		0
Impaired loans without a valuation allowance, Average Recorded Investment	0	14	0	19
Impaired loans without a valuation allowance, Interest Income Recognized	0	0	0	0
Impaired loans with a valuation allowance, Average Recorded Investment	0	13	0	38
Impaired loans with a valuation allowance, Interest Income Recognized	0	0	0	0
Purchased Credit Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	2,219		2,219		1,663
Impaired loans with a valuation allowance, Unpaid Principal Balance	2,717		2,717		2,055
Impaired loans with a valuation allowance, Related Allowance	0		0		156
Impaired loans with a valuation allowance, Average Recorded Investment	2,134	3,628	1,976	2,418
Impaired loans with a valuation allowance, Interest Income Recognized	41	0	43
Impaired loans with a valuation allowance, Interest Income (Expense) Recognized				(7)
Purchased Credit Impaired Loans [Member] \| Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	16		16		17
Impaired loans with a valuation allowance, Unpaid Principal Balance	99		99		99
Impaired loans with a valuation allowance, Related Allowance	0		0		17
Impaired loans with a valuation allowance, Average Recorded Investment	490	2,529	333	1,686
Impaired loans with a valuation allowance, Interest Income Recognized	0	0	1
Impaired loans with a valuation allowance, Interest Income (Expense) Recognized				(9)
Purchased Credit Impaired Loans [Member] \| Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	1,870		1,870		1,205
Impaired loans with a valuation allowance, Unpaid Principal Balance	2,138		2,138		1,371
Impaired loans with a valuation allowance, Related Allowance	0		0		74
Impaired loans with a valuation allowance, Average Recorded Investment	1,168	1,099	1,174	732
Impaired loans with a valuation allowance, Interest Income Recognized	38	0	39	2
Purchased Credit Impaired Loans [Member] \| Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	0		0		0
Impaired loans with a valuation allowance, Unpaid Principal Balance	0		0		0
Impaired loans with a valuation allowance, Related Allowance	0		0		0
Impaired loans with a valuation allowance, Average Recorded Investment	116	0	77	0
Impaired loans with a valuation allowance, Interest Income Recognized	0	0	0	0
Purchased Credit Impaired Loans [Member] \| Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	303		303		396
Impaired loans with a valuation allowance, Unpaid Principal Balance	445		445		534
Impaired loans with a valuation allowance, Related Allowance	0		0		59
Impaired loans with a valuation allowance, Average Recorded Investment	338	0	361	0
Impaired loans with a valuation allowance, Interest Income Recognized	3	0	3	0
Purchased Credit Impaired Loans [Member] \| Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with a valuation allowance, Recorded Investment	30		30		45
Impaired loans with a valuation allowance, Unpaid Principal Balance	35		35		51
Impaired loans with a valuation allowance, Related Allowance	0		0		$ 6
Impaired loans with a valuation allowance, Average Recorded Investment	22	0	31	0
Impaired loans with a valuation allowance, Interest Income Recognized	$ 0	$ 0	$ 0	$ 0

Impaired financing receivable with related allowance interest income (expense) cash basis method.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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