STOCK PLANS (Tables)

12 Months Ended

Dec. 31, 2016

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

Summary of stock option activity

The following table summarizes stock option activity for the year ended December 31, 2016 under all Plans:

	Year Ended December 31,
	2016
	Options		Weighted Average Exercise Price
Balance at beginning of year	2,194,649		$	42.85
Options granted	247,310		58.14
Options exercised	(820,972	)	30.51
Options canceled	(11,285	)	66.48
Balance at end of year	1,609,702		51.32
Exercisable at end of year	1,151,320		46.56

Weighted average assumptions used for estimating fair value of options granted

The weighted average assumptions for each of the three years ended December 31, 2016 were as follows:

	Year Ended December 31,
	2016			2015			2014
Expected volatility	28.86		%	30.73		%	32.21		%
Dividend yield	1.70		%	1.48		%	1.41		%
Risk-free interest rate	1.27		%	1.32		%	1.61		%
Expected option life (years)	4.5			4.5			4.4
Weighted average fair value per option granted during the year	$	12.55		$	16.35		$	17.52

Summary of nonvested stock options

The following table summarizes non-vested stock options for the year ended December 31, 2016:

	Year Ended December 31, 2016
	Number of Options		Weighted Average Fair Value at Grant Date
Balance at beginning of year	387,222		$	16.66
Granted	247,310		12.55
Vested	(168,050	)	17.05
Forfeited	(8,100	)	15.43
Balance at end of year	458,382		14.32

Summary of information about awards outstanding, by exercise price range

The following table summarizes information about awards outstanding as of December 31, 2016:

	Outstanding				Exercisable
Exercise Price Range	Number of Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Life (years)	Number of Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Life (years)
Under $49.99	823,040	$	37.00	4.5	823,040	$	37.00	4.5
$50.00 - $59.99	254,517	58.06		9.1	4,760	53.96		6.8
Over $60.00	532,145	70.25		7.6	323,520	70.76		7.3
	1,609,702			6.3	1,151,320			5.3

Summary of restricted share award activity

The following table summarizes restricted share award activity for the year ended December 31, 2016 under all Plans:

	Year Ended December 31,
	2016
	Shares		Weighted Average Grant Date Fair Value
Balance at beginning of year	44,629		$	61.84
Shares granted	13,470		79.43
Shares vested	(11,940	)	70.80
Shares forfeited	—		—
Balance at end of year	46,159		64.65

Summary of restricted stock unit activity

The following table summarizes RSU and PSU activity for the year ended December 31, 2016 under all Plans:

	Year Ended December 31,
	2016
	Units		Weighted Average Grant Date Fair Value
Balance at beginning of year	221,532		$	59.10
Units granted	188,635		58.33
Units vested	(25,891	)	43.83
Units forfeited	(7,492	)	60.28
Balance at end of year	376,784		59.75