Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 538,373	$ 538,373
Gross Carrying Amount	47,625	47,625
Accumulated Amortization	(29,756)	(25,242)
Net Carrying Amount	17,869	22,383
Core Deposits [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	26,625	26,625
Accumulated Amortization	(18,516)	(15,618)
Net Carrying Amount	8,109	11,007
Customer Relationships [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21,000	21,000
Accumulated Amortization	(11,240)	(9,624)
Net Carrying Amount	$ 9,760	$ 11,376