Fair Value Disclosures - Contingent Consideration Liability Change in Amount (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Change in Contingent Consideration Liability [Roll Forward]
Beginning balance	$ 160	$ 259
Contingent consideration from new acquisition	0	0
Payment of contingent consideration	121	129
Adjustment of contingent consideration	16	30
Ending balance	55	160
Girard Partners [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning balance	160	259
Contingent consideration from new acquisition	0	0
Payment of contingent consideration	121	129
Adjustment of contingent consideration	16	30
Ending balance	$ 55	$ 160