STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2018

STOCK-BASED COMPENSATION

Summary of restricted stock units, performance-based stock units, and weighted average grant date fair values

	Employee Service-Based  Awards				Employee Performance-Based Awards				Director Awards
	Units		Weighted  Average  Grant Date  Fair Value		Units		Weighted  Average  Grant Date  Fair Value		Units		Weighted  Average  Grant Date  Fair Value
Nonvested at December 31, 2017	1,183,039		$	14.30	632,636		$	18.87	98,406		$	12.66
Granted	560,657		15.68		267,522		17.93		—		—
Vested	(352,106	)	16.14		(135,200	)	25.95		(21,928	)	12.77
Forfeited	(47,808	)	12.58		(26,479	)	18.38		—		—
Nonvested at March 31, 2018	1,343,782		$	14.45	738,479		$	17.25	76,478		$	12.63