Off-Balance Sheet Arrangements Commitments Guarantees and Contingencies (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Commitments And Guarantees [Line Items]
Credit card guarantees	$ 8.5	$ 8.1
Fully collateralized credit card guarantees	$ 1.3	$ 1.4