Revenue Recognition - Summary of Non Interest Income, Segregated by Revenue Streams in-Scope and Out-of-Scope of Topic 606 (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Noninterest income:
Gain on OREO, net	$ 399	$ 0
Other	1,682	1,798
Total noninterest income	13,681	11,640
Service Charges on Deposit Accounts [Member]
Noninterest income:
Revenue from contract with customer	3,985	4,776
Trust and Investment Services [Member]
Noninterest income:
Revenue from contract with customer	2,611	2,420
Bankcard Services [Member]
Noninterest income:
Revenue from contract with customer	350	577
Accounting Standards Update 2014-09 [Member]
Noninterest income:
Gain on OREO, net	429	10
Other	1,682	1,798
Total noninterest income	9,057	9,581
Accounting Standards Update 2014-09 [Member] | Service Charges on Deposit Accounts [Member]
Noninterest income:
Revenue from contract with customer	3,985	4,776
Accounting Standards Update 2014-09 [Member] | Trust and Investment Services [Member]
Noninterest income:
Revenue from contract with customer	2,611	2,420
Accounting Standards Update 2014-09 [Member] | Bankcard Services [Member]
Noninterest income:
Revenue from contract with customer	350	577
Accounting Standards Update 2014-09 Not Adopted [Member]
Noninterest income:
Total noninterest income	$ 4,624	$ 2,059