Loans and Allowance for Loan Losses - Credit Risk Profile of Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Credit risk profile of portfolio
Loans	$ 5,782,663	$ 5,535,426
Special Mention (Watch)
Credit risk profile of portfolio
Loans	100,831	152,939
Special Mention (Watch) Covid 19 Deferrals
Credit risk profile of portfolio
Loans		678
Substandard
Credit risk profile of portfolio
Loans	43,405	14,464
Acceptable and Above
Credit risk profile of portfolio
Loans	5,638,427	5,367,345
Mortgage warehouse lines of credit
Credit risk profile of portfolio
Loans	781,437	1,605,745
Mortgage warehouse lines of credit | Special Mention (Watch)
Credit risk profile of portfolio
Loans		222
Mortgage warehouse lines of credit | Acceptable and Above
Credit risk profile of portfolio
Loans	781,437	1,605,523
Residential real estate
Credit risk profile of portfolio
Loans	843,101	678,848
Residential real estate | Special Mention (Watch)
Credit risk profile of portfolio
Loans	946	853
Residential real estate | Substandard
Credit risk profile of portfolio
Loans	419	2,761
Residential real estate | Acceptable and Above
Credit risk profile of portfolio
Loans	841,736	674,851
Residential real estate | Covid 19 | Special Mention (Watch) Covid 19 Deferrals
Credit risk profile of portfolio
Loans		383
Multi-family and healthcare financing
Credit risk profile of portfolio
Loans	3,528,199	2,749,020
Multi-family and healthcare financing | Special Mention (Watch)
Credit risk profile of portfolio
Loans	93,561	145,050
Multi-family and healthcare financing | Substandard
Credit risk profile of portfolio
Loans	36,760
Multi-family and healthcare financing | Acceptable and Above
Credit risk profile of portfolio
Loans	3,397,878	2,603,785
Multi-family and healthcare financing | Covid 19 | Special Mention (Watch) Covid 19 Deferrals
Credit risk profile of portfolio
Loans		185
Commercial and commercial real estate
Credit risk profile of portfolio
Loans	520,199	387,294
Commercial and commercial real estate | Special Mention (Watch)
Credit risk profile of portfolio
Loans	2,483	2,620
Commercial and commercial real estate | Special Mention (Watch) Covid 19 Deferrals
Credit risk profile of portfolio
Loans		110
Commercial and commercial real estate | Substandard
Credit risk profile of portfolio
Loans	6,055	9,591
Commercial and commercial real estate | Acceptable and Above
Credit risk profile of portfolio
Loans	511,661	374,973
Agricultural production and real estate
Credit risk profile of portfolio
Loans	97,060	101,268
Agricultural production and real estate | Special Mention (Watch)
Credit risk profile of portfolio
Loans	3,820	4,160
Agricultural production and real estate | Substandard
Credit risk profile of portfolio
Loans	158	2,100
Agricultural production and real estate | Acceptable and Above
Credit risk profile of portfolio
Loans	93,082	95,008
Consumer and margin loans
Credit risk profile of portfolio
Loans	12,667	13,251
Consumer and margin loans | Special Mention (Watch)
Credit risk profile of portfolio
Loans	21	34
Consumer and margin loans | Substandard
Credit risk profile of portfolio
Loans	13	12
Consumer and margin loans | Acceptable and Above
Credit risk profile of portfolio
Loans	$ 12,633	$ 13,205