Credit Quality - Schedule of Reasons For Modification Troubled Debt Restructuring Loans (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	$ 77,436	$ 58,369
Interest rate reduction [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	11,662	1,685
Interest rate reduction and change in terms [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	3,039	1,733
Forgiveness of principal [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	252	0
Transfer of asset [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	121	0
Concession of principal and term [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	24	0
Extended maturity [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	4,879	0
Change in terms [Member]
Disclosure Details Of Reasons For Modification Troubled Debt Restrusturing Loans [Line Items]
Troubled debt restructuring	$ 57,459	$ 54,951