Goodwill and Intangible Assets - Additional Information (Detail) $ in Thousands	1 Months Ended	6 Months Ended
	Jan. 31, 2019 USD ($)	Jun. 30, 2020 USD ($) reportingUnit	Dec. 31, 2019 USD ($)	Jan. 04, 2019 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill		$ 156,277	$ 156,277	$ 19,800
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 156,277	156,277	$ 19,800
Number of reporting units | reportingUnit		1
Core Deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		$ 3,800	$ 4,300
Finite-lived intangible assets acquired	$ 3,700