(Reserve for Unfunded Commitments) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounting Standards Update 2016-13 [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 0	$ 0	$ 9,139	$ 0
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	10,084	2,511	2,367	2,506
Provision (benefit) charged to non-interest expense	655	26	(767)	31
Ending balance	$ 10,739	$ 2,537	$ 10,739	$ 2,537