Loans and Leases Receivable and Allowance for Credit Losses - Schedule of Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 144,176	$ 56,379
Charge-offs	(14,646)	(19,140)
Recoveries	2,125	429
Provision (benefit) for credit losses on loans and leases	(2,919)	31,786
Ending balance	128,736	149,283
Multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	12,620	6,157
Charge-offs	(1,132)	0
Recoveries	0	0
Provision (benefit) for credit losses on loans and leases	(3,462)	422
Ending balance	8,026	8,750
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	12,239	15,556
Charge-offs	(635)	(97)
Recoveries	260	54
Provision (benefit) for credit losses on loans and leases	(4,361)	2,534
Ending balance	7,503	18,806
Commercial real estate owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	9,512	2,235
Charge-offs	(142)	0
Recoveries	8	3
Provision (benefit) for credit losses on loans and leases	(3,443)	516
Ending balance	5,935	8,527
Commercial real estate non-owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	19,452	6,243
Charge-offs	0	(12,797)
Recoveries	10	0
Provision (benefit) for credit losses on loans and leases	(7,841)	17,166
Ending balance	11,621	18,530
Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	5,871	1,262
Charge-offs	0	0
Recoveries	5	3
Provision (benefit) for credit losses on loans and leases	(1,773)	767
Ending balance	4,103	1,934
Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,977	3,218
Charge-offs	(50)	0
Recoveries	10	29
Provision (benefit) for credit losses on loans and leases	(728)	(585)
Ending balance	3,209	4,180
Manufactured housing
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	5,190	1,060
Charge-offs	0	0
Recoveries	0	0
Provision (benefit) for credit losses on loans and leases	(390)	125
Ending balance	4,800	4,987
Installment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	75,315	20,648
Charge-offs	(12,687)	(6,246)
Recoveries	1,832	340
Provision (benefit) for credit losses on loans and leases	19,079	10,841
Ending balance	$ 83,539	83,569
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		79,829
Cumulative Effect, Period of Adoption, Adjustment \| Multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		2,171
Cumulative Effect, Period of Adoption, Adjustment \| Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		759
Cumulative Effect, Period of Adoption, Adjustment \| Commercial real estate owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		5,773
Cumulative Effect, Period of Adoption, Adjustment \| Commercial real estate non-owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		7,918
Cumulative Effect, Period of Adoption, Adjustment \| Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		(98)
Cumulative Effect, Period of Adoption, Adjustment \| Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		1,518
Cumulative Effect, Period of Adoption, Adjustment \| Manufactured housing
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		3,802
Cumulative Effect, Period of Adoption, Adjustment \| Installment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		$ 57,986

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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