STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of restricted stock awards

The following table summarizes information about restricted stock awards for the three months ended March 31, 2018:

Restricted Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2018	604,933		$	54.23
Granted	149,200		$	53.43
Vested	(25,558	)	$	52.65
Forfeited	(6,772	)	$	52.65
Balance at March 31, 2018	721,803		$	54.13

Summary of performance stock awards

The following table summarizes information about performance stock awards for the three months ended March 31, 2018:

Performance Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2018	190,129		$	55.63
Granted	—		$	—
Vested	(8,696	)	$	54.26
Forfeited	(7,056	)	$	54.64
Balance at March 31, 2018	174,377		$	55.74