STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2017

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, 2017:

Restricted Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2017	510,041		$	52.65
Granted	295,568		$	56.00
Vested	(115,365	)	$	53.89
Forfeited	(47,784	)	$	51.35
Balance at September 30, 2017	642,460		$	54.07

Summary of performance stock awards

The following table summarizes information about performance stock awards for the nine months ended September 30, 2017:

Performance Stock	Number of Shares		Weighted Average Grant-Date Fair Value
Balance at January 1, 2017	220,882		$	54.69
Granted	167,964		$	55.84
Vested	(25,168	)	$	54.84
Forfeited	(25,544	)	$	56.19
Balance at September 30, 2017	338,134		$	55.25