Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Proceeds from the sales and maturities of securities available-for-sale	$ 19.4	$ 261.6	$ 262.1
Net unrealized (losses) gains on trading securities	(0.3)	(0.4)
Net realized gains	$ 0.1	$ 1.7
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Business combination, contingent consideration payment period	18 months
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Business combination, contingent consideration payment period	24 months