SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Weighted-average shares:
Weighted average number of shares outstanding, basic (in shares)	30,722	32,388	35,862
Total weighted average shares outstanding, basic (in shares)	30,743	32,409	35,952
Earnings per common share—Basic
Net income	$ 282,810	$ 245,368	$ 181,848
Net income available to common shareholders—Basic	$ 282,619	$ 245,211	$ 181,390
Net income per common share, basic (in dollars per share)	$ 9.20	$ 7.57	$ 5.06
Weighted average number of shares outstanding, basic (in shares)	30,722	32,388	35,862
Effect of diluted shares (in shares)	1,119	1,283	1,835
Weighted-average shares outstanding, diluted (in shares)	31,841	33,671	37,697
Net income per common share, diluted (in dollars per share)	$ 8.88	$ 7.28	$ 4.81
RSAs
Weighted-average shares:
Weighted average number of shares outstanding, basic (in shares)	21	21	90
Earnings per common share—Basic
Less: Undistributed earnings allocated to RSAs	$ (191)	$ (157)	$ (458)
Weighted average number of shares outstanding, basic (in shares)	21	21	90
Common Stock
Weighted-average shares:
Weighted average number of shares outstanding, basic (in shares)	30,722	32,388	35,862
Earnings per common share—Basic
Weighted average number of shares outstanding, basic (in shares)	30,722	32,388	35,862