STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 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 nine months ended September 30, 2018:

Restricted Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2018	604,933		$	54.23
Granted	308,016		$	54.39
Vested	(172,946	)	$	54.61
Forfeited	(41,244	)	$	54.04
Balance at September 30, 2018	698,759		$	54.22

Summary of performance stock awards

The following table summarizes information about performance stock awards for the nine months ended September 30, 2018:

Performance Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2018	190,129		$	55.63
Granted	171,584		$	55.71
Vested	(8,696	)	$	54.26
Forfeited	(27,181	)	$	55.43
Balance at September 30, 2018	325,836		$	55.73