Net Income Per Common Share - Basic and Diluted Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic
Net income applicable to common stock	$ 40,063	$ 29,992	$ 138,838	$ 52,130
Average common shares outstanding (shares)	56,146,285	56,185,884	56,237,056	56,294,984
Net income per common share - basic (usd per share)	$ 0.71	$ 0.53	$ 2.47	$ 0.93
Diluted
Net income applicable to common stock	$ 40,063	$ 29,992	$ 138,838	$ 52,130
Average common shares outstanding (shares)	56,146,285	56,185,884	56,237,056	56,294,984
Effect of dilutive stock-based compensation (shares)	300,899	200,269	296,038	173,593
Average common shares outstanding - diluted (shares)	56,447,184	56,386,153	56,533,094	56,468,577
Net income per common share - diluted (usd per share)	$ 0.71	$ 0.53	$ 2.46	$ 0.92