Loans Receivable, Net - Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method Excluding PCI Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Allowance for credit losses on loans
Balance at beginning of period	$ 53,876	$ 38,509	$ 60,735	$ 16,852
Credit loss expense (benefit)	(4,109)	32,836	(11,024)	50,075
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				2,639
Charge-offs	(163)	(15,411)	(939)	(16,964)
Recoveries	549	416	1,381	1,047
Balance at end of period	50,153	56,350	50,153	56,350
Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				2,701
Commercial and industrial
Allowance for credit losses on loans
Balance at beginning of period	4,404	4,979	5,390	1,458
Credit loss expense (benefit)	1,962	(106)	958	(275)
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				1,221
Charge-offs	(50)	(575)	(83)	(575)
Recoveries	50	29	101	82
Balance at end of period	6,366	4,327	6,366	4,327
Commercial and industrial | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				2,416
Commercial real estate – owner occupied
Allowance for credit losses on loans
Balance at beginning of period	6,350	2,765	15,054	2,893
Credit loss expense (benefit)	515	5,166	(8,225)	6,120
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				26
Charge-offs	(64)	(2,252)	(64)	(2,253)
Recoveries	26	2	62	4
Balance at end of period	6,827	5,681	6,827	5,681
Commercial real estate – owner occupied | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				(1,109)
Commercial Real Estate – Investor
Allowance for credit losses on loans
Balance at beginning of period	33,037	8,860	26,703	9,883
Credit loss expense (benefit)	(9,902)	30,131	(3,336)	34,208
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				260
Charge-offs	0	(12,037)	(345)	(12,062)
Recoveries	5	32	118	92
Balance at end of period	23,140	26,986	23,140	26,986
Commercial Real Estate – Investor | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				(5,395)
Residential Real Estate
Allowance for credit losses on loans
Balance at beginning of period	8,818	17,685	11,818	2,002
Credit loss expense (benefit)	3,081	(1,891)	284	10,749
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				109
Charge-offs	(12)	(6)	(254)	(1,351)
Recoveries	292	320	331	766
Balance at end of period	12,179	16,108	12,179	16,108
Residential Real Estate | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				3,833
Consumer
Allowance for credit losses on loans
Balance at beginning of period	1,267	4,220	1,770	591
Credit loss expense (benefit)	235	(464)	(705)	(727)
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				1,023
Charge-offs	(37)	(541)	(193)	(723)
Recoveries	176	33	769	103
Balance at end of period	1,641	3,248	1,641	3,248
Consumer | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				2,981
Unallocated
Allowance for credit losses on loans
Balance at beginning of period	0	0	0	25
Credit loss expense (benefit)	0	0	0	0
Initial allowance for credit losses on purchased with credit deterioration (“PCD”) loans				0
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Balance at end of period	$ 0	$ 0	$ 0	0
Unallocated | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period				$ (25)