Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Jan. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 260,725	$ 47,625
Accumulated Amortization		36,143	29,756
Net Carrying Amount		224,582	17,869
Sterling and Bend
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, useful life	10 years
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		145,725	26,625
Accumulated Amortization		22,183	18,516
Net Carrying Amount		123,542	8,109
Core deposits | Sterling and Bend
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 119,100
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		115,000	21,000
Accumulated Amortization		13,960	11,240
Net Carrying Amount		$ 101,040	$ 9,760
Customer relationships | Sterling and Bend
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 94,000