Loans - Summary of Impairment by Class of Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	$ 28,568	$ 16,589
Interest income recognized during impairment	90	102
PCD Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	23,721
Interest income recognized during impairment	148
Total Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	21,185	13,849
Interest income recognized during impairment	70	88
Total Real Estate Loans [Member] \| PCD Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	20,128
Interest income recognized during impairment	125
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	5,567	5,945
Interest income recognized during impairment	37	62
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	14,795	7,787
Interest income recognized during impairment	31	25
Commercial Real Estate [Member] \| PCD Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	20,128
Interest income recognized during impairment	125
Land, Development, Construction [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	823	117
Interest income recognized during impairment	2	1
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	7,254	2,600
Interest income recognized during impairment	18	12
Commercial and Industrial [Member] \| PCD Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	3,593
Interest income recognized during impairment	23
Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	129	140
Interest income recognized during impairment	$ 2	$ 2

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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