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
	Mar. 31, 2021	Mar. 31, 2020
Allowance for credit losses on loans
Balance at beginning of period	$ 60,735	$ 16,852
Credit loss expense (benefit)	(1,039)	8,597
Initial allowance for credit losses on PCD loans		2,639
Charge-offs	(356)	(1,384)
Recoveries	636	230
Balance at end of period	59,976	29,635
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	5,390	1,458
Credit loss expense (benefit)	(2,875)	1,529
Initial allowance for credit losses on PCD loans		1,221
Charge-offs	0	0
Recoveries	26	25
Balance at end of period	2,541	6,649
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	15,054	2,893
Credit loss expense (benefit)	(7,257)	1,286
Initial allowance for credit losses on PCD loans		26
Charge-offs	0	0
Recoveries	30	0
Balance at end of period	7,827	3,096
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	26,703	9,883
Credit loss expense (benefit)	10,149	2,377
Initial allowance for credit losses on PCD loans		260
Charge-offs	(34)	0
Recoveries	104	34
Balance at end of period	36,922	7,159
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	11,818	2,002
Credit loss expense (benefit)	(335)	3,585
Initial allowance for credit losses on PCD loans		109
Charge-offs	(242)	(1,275)
Recoveries	39	163
Balance at end of period	11,280	8,417
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	1,770	591
Credit loss expense (benefit)	(721)	(180)
Initial allowance for credit losses on PCD loans		1,023
Charge-offs	(80)	(109)
Recoveries	437	8
Balance at end of period	1,406	4,314
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	25
Credit loss expense (benefit)	0	0
Initial allowance for credit losses on PCD loans		0
Charge-offs	0	0
Recoveries	0	0
Balance at end of period	$ 0	0
Unallocated | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Balance at beginning of period		$ (25)