Shareholders' Equity and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 27, 2019	Aug. 26, 2019
Shareholders' Equity and Earnings Per Share
Common stock, shares authorized	100,000,000				100,000,000				100,000,000	100,000,000		100,000,000	60,000,000
Reconciliation of factors used in computing basic and diluted earnings per common share
Net income	$ 11,623	$ 11,197	$ 10,618	$ 1,861	$ 5,685	$ 11,277	$ 11,353	$ 12,146	$ 35,299	$ 40,461	$ 35,331
Weighted average common shares outstanding for basic earnings per common share (in shares)									59,478,343	46,684,384	41,469,211
Dilutive potential common shares									690,796	1,221,845	713,728
Shares used in computing diluted earnings per common share (in shares)									60,169,139	47,906,229	42,182,939
Basic earnings per share (in dollars per share)	$ 0.19	$ 0.19	$ 0.18	$ 0.03	$ 0.10	$ 0.26	$ 0.26	$ 0.28	$ 0.59	$ 0.87	$ 0.85
Diluted earnings per share (in dollars per share)	$ 0.19	$ 0.19	$ 0.18	$ 0.03	$ 0.10	$ 0.26	$ 0.26	$ 0.28	$ 0.59	$ 0.84	$ 0.84
Number of shares not in computing diluted earnings per common share									1,524,757	789,065	534,106