EARNINGS PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 41,477	$ 50,856	$ 107,498	$ 149,398
Denominator for basic earnings per share - weighted average shares	97,247,080	98,517,025	97,400,942	98,177,802
Effect of dilutive securities -
Employee stock awards	761,653	560,698	716,521	545,371
Denominator for diluted earnings per share - adjusted weighted average shares	98,008,733	99,077,723	98,117,463	98,723,173
Basic	$ 0.43	$ 0.52	$ 1.10	$ 1.52
Diluted	$ 0.42	$ 0.51	$ 1.10	$ 1.51