(Reserve for Unfunded Commitments) (Detail) - SEC Schedule, 12-09, Allowance, Credit Loss [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 2,537	$ 2,596	$ 2,506	$ 2,362
(Benefit) provision charged to expense	(68)	28	(37)	262
Ending balance	$ 2,469	$ 2,624	$ 2,469	$ 2,624