Loans Receivable and Allowance for Credit Losses (Schedule of Allowance for Loan Losses by Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 80,740	$ 101,466
Provision benefit to operations	(6,400)	(15,000)
Recoveries of loans previously charged-off	2,036	1,107
Loans charged-off	(101)	(1,982)
Balance at end of period	76,275	85,591
Mortgage Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	52,104	68,307
Provision benefit to operations	(1,995)	(13,467)
Recoveries of loans previously charged-off	10	276
Loans charged-off	(23)	(918)
Balance at end of period	50,096	54,198
Commercial Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	26,343	27,084
Provision benefit to operations	(4,404)	(467)
Recoveries of loans previously charged-off	1,860	528
Loans charged-off	0	(843)
Balance at end of period	23,799	26,302
Consumer Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	2,293	6,075
Provision benefit to operations	(1)	(1,066)
Recoveries of loans previously charged-off	166	303
Loans charged-off	(78)	(221)
Balance at end of period	$ 2,380	$ 5,091