Loans and Allowance for Loan Losses - Summary of Loans By Classification (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans and Allowance for Loan Losses
Loans	$ 3,028,310	$ 2,058,127
Allowance for loan losses	15,842	12,704	$ 8,311	$ 6,250
Loans and Leases Receivable, Net Amount, Total	$ 3,012,468	2,045,423
Minimum
Loans and Allowance for Loan Losses
Repayment Of Warehouse Term	30 days
Mortgage warehouse lines of credit
Loans and Allowance for Loan Losses
Loans	$ 765,151	337,332
Allowance for loan losses	1,913	1,068	283	373
Residential real estate
Loans and Allowance for Loan Losses
Loans	413,835	410,871
Allowance for loan losses	2,042	1,986	1,587	2,170
Multi-family and healthcare financing
Loans and Allowance for Loan Losses
Loans	1,347,125	914,393
Allowance for loan losses	7,018	6,030	3,502	1,962
Commercial and commercial real estate
Loans and Allowance for Loan Losses
Loans	398,601	299,194
Allowance for loan losses	4,173	3,051	2,362	1,374
Agricultural production and real estate
Loans and Allowance for Loan Losses
Loans	85,210	79,255
Allowance for loan losses	523	429	320	269
Consumer and margin loans
Loans and Allowance for Loan Losses
Loans	18,388	17,082
Allowance for loan losses	$ 173	$ 140	$ 257	$ 102

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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