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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 37,393	$ 52,703	$ 66,021	$ 98,542
Denominator for basic earnings per share - weighted average shares	97,220,748	98,083,799	97,478,719	98,005,379
Effect of dilutive securities -
Employee stock awards	767,852	564,585	693,689	537,568
Denominator for diluted earnings per share - adjusted weighted average shares	97,988,600	98,648,384	98,172,408	98,542,947
Basic	$ 0.38	$ 0.54	$ 0.68	$ 1.01
Diluted	$ 0.38	$ 0.53	$ 0.67	$ 1.00