Condensed Parent Company Only Financial Statements - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash	$ 253,782	$ 63,794	$ 63,120	$ 54,806
Total assets	4,014,324	3,235,049
Liabilities
Subordinated debt	73,744	14,872	14,860
Accrued interest payable	1,940	846
Other liabilities	30,638	21,683
Total liabilities	3,679,898	2,938,408
Stockholders' Equity
Preferred stock, $0.01 par value per share; 1,000,000 shares authorized; no shares issued	0	0
Common stock $0.01 par value per share; 40,000,000 shares authorized; 11,937,795 shares issued and outstanding at December 31, 2020 and 11,825,331 shares issued and outstanding at December 31, 2019	119	118
Additional paid-in capital	97,137	94,170
Retained earnings	214,977	191,843
Accumulated other comprehensive income	22,193	10,510
Total stockholders' equity	334,426	296,641	255,297	231,810
Total liabilities and stockholders' equity	4,014,324	3,235,049
Parent
Assets
Cash	3,302	353	$ 123	$ 345
Investment in subsidiaries	406,032	311,040
Other assets	430	201
Total assets	409,764	311,594
Liabilities
Subordinated debt	73,744	14,872
Accrued interest payable	1,591	78
Other liabilities	3	3
Total liabilities	75,338	14,953
Stockholders' Equity
Preferred stock, $0.01 par value per share; 1,000,000 shares authorized; no shares issued	0	0
Common stock $0.01 par value per share; 40,000,000 shares authorized; 11,937,795 shares issued and outstanding at December 31, 2020 and 11,825,331 shares issued and outstanding at December 31, 2019	119	118
Additional paid-in capital	97,137	94,170
Retained earnings	214,977	191,843
Accumulated other comprehensive income	22,193	10,510
Total stockholders' equity	334,426	296,641
Total liabilities and stockholders' equity	$ 409,764	$ 311,594