Condensed Financial Information - Parent Company Only - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 270,090	$ 282,371
Equity securities, at fair value	14,694	16,473
Investment securities, held to maturity	90,766	123,975
Other assets	110,293	54,744
Total Assets	7,664,297	6,711,236
Liabilities and Stockholders' Equity
Other liabilities	113,730	59,686
Subordinated debentures	118,257	118,220
Total stockholders’ equity	763,784	725,263	$ 623,739	$ 583,122
Total Liabilities and Stockholders’ Equity	7,664,297	6,711,236
Parent Company
Assets
Cash and due from banks	28,366	29,981
Equity securities, at fair value	0	1,735
Investment securities, held to maturity	0	1,000
Investment in subsidiaries	843,711	802,079
Other assets	11,274	9,828
Total Assets	883,351	844,623
Liabilities and Stockholders' Equity
Other liabilities	1,310	1,140
Subordinated debentures	118,257	118,220
Total stockholders’ equity	763,784	725,263
Total Liabilities and Stockholders’ Equity	$ 883,351	$ 844,623