Borrowed Funds - Summary of Borrowed Funds by Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Federal funds purchased
Debt Instrument [Line Items]
Balance at End of Period	$ 195,000	$ 157,975
Weighted Average Interest Rate	1.62%	2.52%
Maximum Outstanding at Month End During the Period	$ 200,000	$ 157,975
Average Amount Outstanding During the Year	$ 135,720	$ 89,325
Weighted Average Interest Rate During the Year	2.19%	1.90%
Federal Home Loan Bank
Debt Instrument [Line Items]
Balance at End of Period	$ 112,675	$ 328,465
Weighted Average Interest Rate	2.20%	2.52%
Maximum Outstanding at Month End During the Period	$ 635,830	$ 695,484
Average Amount Outstanding During the Year	$ 226,728	$ 426,755
Weighted Average Interest Rate During the Year	2.43%	1.97%
Trust preferred borrowings
Debt Instrument [Line Items]
Balance at End of Period	$ 67,011	$ 67,011
Weighted Average Interest Rate	3.62%	4.51%
Maximum Outstanding at Month End During the Period	$ 67,011	$ 67,011
Average Amount Outstanding During the Year	$ 67,011	$ 67,011
Weighted Average Interest Rate During the Year	4.14%	3.84%
Senior debt
Debt Instrument [Line Items]
Balance at End of Period	$ 98,605	$ 98,388
Weighted Average Interest Rate	4.78%	4.50%
Maximum Outstanding at Month End During the Period	$ 98,605	$ 98,388
Average Amount Outstanding During the Year	$ 98,492	$ 98,275
Weighted Average Interest Rate During the Year	4.79%	4.80%
Other borrowed funds
Debt Instrument [Line Items]
Balance at End of Period	$ 15,997	$ 47,949
Weighted Average Interest Rate	0.10%	0.23%
Maximum Outstanding at Month End During the Period	$ 55,400	$ 71,584
Average Amount Outstanding During the Year	$ 29,786	$ 39,314
Weighted Average Interest Rate During the Year	0.30%	0.12%