Condensed Financial Information - Parent Company Only - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and Cash Equivalents, at Carrying Value	$ 282,371	$ 208,599
Equity securities, at fair value	16,473	15,921
Investment securities, held to maturity	123,975	153,646
Other assets	54,744	42,308
TOTAL ASSETS	6,711,236	5,806,093
LIABILITIES AND STOCKHOLDERS’ EQUITY
Other liabilities	59,686	41,634
Subordinated debentures	118,220	105,027
Total stockholders’ equity	725,263	623,739	$ 583,122	$ 550,044
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	6,711,236	5,806,093
Parent Company
ASSETS
Cash and Cash Equivalents, at Carrying Value	29,981	23,285
Equity securities, at fair value	1,735	2,743
Investment securities, held to maturity	1,000	1,000
Investment in subsidiaries	802,079	695,571
Other assets	9,828	7,182
TOTAL ASSETS	844,623	729,781
LIABILITIES AND STOCKHOLDERS’ EQUITY
Other liabilities	1,140	1,015
Subordinated debentures	118,220	105,027
Total stockholders’ equity	725,263	623,739
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 844,623	$ 729,781