Loans and Allowance for Credit Losses on Loans - Summary of Loans By Classification (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)
Loans and Allowance for Loan Losses
Loans	$ 8,627,048	$ 7,470,872
Less: ACL-Loans	51,838	44,014	$ 32,102
Loans receivable	8,575,210	7,426,858
Accrued interest on loans, excluded from amortized cost of loans	42,600	35,000
Mortgage warehouse lines of credit
Loans and Allowance for Loan Losses
Loans	604,445	464,785
Less: ACL-Loans	1,664	1,249	1,941
Residential real estate
Loans and Allowance for Loan Losses
Loans	1,215,252	1,178,401
Less: ACL-Loans	7,378	7,029	4,547
Healthcare financing
Loans and Allowance for Loan Losses
Loans	1,941,204	1,604,341
Less: ACL-Loans	11,753	9,882	5,618
Multi-family financing
Loans and Allowance for Loan Losses
Loans	3,566,530	3,135,535
Less: ACL-Loans	19,851	16,781	15,131
Commercial and commercial real estate
Loans and Allowance for Loan Losses
Loans	1,194,320	978,661
Less: ACL-Loans	10,482	8,326	4,102
Mortgage servicing rights collateralized	672,900	497,000
Commercial and commercial real estate | Non-owner occupied commercial real estate
Loans and Allowance for Loan Losses
Loans	$ 9,100	12,800
Commercial and commercial real estate | Non-owner occupied commercial real estate | Minimum
Loans and Allowance for Loan Losses
Percentage of loans to be forgiven	1
Agricultural production and real estate
Loans and Allowance for Loan Losses
Loans	$ 89,516	95,651
Less: ACL-Loans	543	565	597
Consumer and margin loans
Loans and Allowance for Loan Losses
Loans	15,781	13,498
Less: ACL-Loans	$ 167	$ 182	$ 166