Loans Receivable and Allowance for Credit Losses (Schedule of Summarized Loans Receivable) (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	$ 9,673,920	$ 9,593,879
Premiums on purchased loans	1,482	1,451
Net deferred fees and unearned discounts	(12,520)	(13,706)
Total gross loans	9,662,882	9,581,624
Mortgage Portfolio Segment
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	7,226,005	7,077,571
Mortgage Portfolio Segment | Residential
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	1,194,613	1,202,638
Mortgage Portfolio Segment | Commercial
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	3,937,216	3,827,370
Mortgage Portfolio Segment | Multi-Family
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	1,394,761	1,364,397
Mortgage Portfolio Segment | Construction
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	699,415	683,166
Commercial Loans
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	2,131,326	2,188,866
Consumer Loans
Servicing Liability at Amortized Cost [Line Items]
Total gross loans	$ 316,589	$ 327,442