EARNINGS PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 50,888	$ 37,393	$ 98,203	$ 66,021
Denominator for basic earnings per share - weighted average shares	96,123,645	97,220,748	96,496,720	97,478,719
Effect of dilutive securities -
Employee stock awards	886,067	767,852	869,920	693,689
Denominator for diluted earnings per share - adjusted weighted average shares	97,009,712	97,988,600	97,366,640	98,172,408
Basic	$ 0.53	$ 0.38	$ 1.02	$ 0.68
Diluted	$ 0.52	$ 0.38	$ 1.01	$ 0.67