Loans and Other Real Estate - Impaired Loans with and without Specific Allowances (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Recorded Investment in Impaired Loans	$ 31,934	$ 22,124
Contractual Unpaid Principal Balance	32,846	22,776
Specific Allowance	222	352
Average Investment in Impaired Loans	22,055	18,342
Interest Income Recognized	97	426
Commercial, secured by real estate
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	23,705	12,478
Loans with related allowance, Recorded Investment in Impaired Loans	3,263	3,470
Recorded Investment in Impaired Loans	26,968	15,948
Loans without related allowance, Contractual Unpaid Principal Balance	23,965	12,630
Loans with related allowance, Contractual Unpaid Principal Balance	3,505	3,706
Contractual Unpaid Principal Balance	27,470	16,336
Specific Allowance	202	228
Loans without related allowance, Average Investment in Impaired Loans	13,594	10,386
Loans with related allowance, Average Investment in Impaired Loans	3,406	4,554
Average Investment in Impaired Loans	17,000	14,940
Loans without related allowance, Interest Income Recognized	30	164
Loans with related allowance, Interest Income Recognized	38	190
Interest Income Recognized	68	354
Commercial, industrial and other
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	1,330	1,391
Loans with related allowance, Recorded Investment in Impaired Loans	106	113
Recorded Investment in Impaired Loans	1,436	1,504
Loans without related allowance, Contractual Unpaid Principal Balance	1,333	1,381
Loans with related allowance, Contractual Unpaid Principal Balance	105	113
Contractual Unpaid Principal Balance	1,438	1,494
Specific Allowance	5	5
Loans without related allowance, Average Investment in Impaired Loans	1,347	1,334
Loans with related allowance, Average Investment in Impaired Loans	105	113
Average Investment in Impaired Loans	1,452	1,447
Loans without related allowance, Interest Income Recognized	4	16
Loans with related allowance, Interest Income Recognized	2	6
Interest Income Recognized	6	22
Equipment finance
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	0	0
Loans with related allowance, Recorded Investment in Impaired Loans	19	23
Recorded Investment in Impaired Loans	19	23
Loans without related allowance, Contractual Unpaid Principal Balance	0	0
Loans with related allowance, Contractual Unpaid Principal Balance	19	23
Contractual Unpaid Principal Balance	19	23
Specific Allowance	8	10
Loans without related allowance, Average Investment in Impaired Loans	0	0
Loans with related allowance, Average Investment in Impaired Loans	21	21
Average Investment in Impaired Loans	21	21
Loans without related allowance, Interest Income Recognized	0	0
Loans with related allowance, Interest Income Recognized	0	0
Interest Income Recognized	0	0
Real estate - residential mortgage
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	1,525	803
Loans with related allowance, Recorded Investment in Impaired Loans	654	1,512
Recorded Investment in Impaired Loans	2,179	2,315
Loans without related allowance, Contractual Unpaid Principal Balance	1,651	815
Loans with related allowance, Contractual Unpaid Principal Balance	835	1,682
Contractual Unpaid Principal Balance	2,486	2,497
Specific Allowance	2	104
Loans without related allowance, Average Investment in Impaired Loans	1,581	233
Loans with related allowance, Average Investment in Impaired Loans	659	926
Average Investment in Impaired Loans	2,240	1,159
Loans without related allowance, Interest Income Recognized	0	0
Loans with related allowance, Interest Income Recognized	5	19
Interest Income Recognized	5	19
Real estate - construction
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	694	1,663
Loans with related allowance, Recorded Investment in Impaired Loans	0	0
Recorded Investment in Impaired Loans	694	1,663
Loans without related allowance, Contractual Unpaid Principal Balance	694	1,661
Loans with related allowance, Contractual Unpaid Principal Balance	0	0
Contractual Unpaid Principal Balance	694	1,661
Specific Allowance	0	0
Loans without related allowance, Average Investment in Impaired Loans	702	82
Loans with related allowance, Average Investment in Impaired Loans	0	0
Average Investment in Impaired Loans	702	82
Loans without related allowance, Interest Income Recognized	10	2
Loans with related allowance, Interest Income Recognized	0	0
Interest Income Recognized	10	2
Home equity and consumer
Financing Receivable, Impaired [Line Items]
Loans without related allowance, Recorded Investment in Impaired Loans	0	0
Loans with related allowance, Recorded Investment in Impaired Loans	638	671
Recorded Investment in Impaired Loans	638	671
Loans without related allowance, Contractual Unpaid Principal Balance	0	0
Loans with related allowance, Contractual Unpaid Principal Balance	739	765
Contractual Unpaid Principal Balance	739	765
Specific Allowance	5	5
Loans without related allowance, Average Investment in Impaired Loans	0	0
Loans with related allowance, Average Investment in Impaired Loans	640	693
Average Investment in Impaired Loans	640	693
Loans without related allowance, Interest Income Recognized	0	0
Loans with related allowance, Interest Income Recognized	8	29
Interest Income Recognized	$ 8	$ 29

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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