STOCK-BASED PLANS (Tables)

12 Months Ended

Dec. 31, 2016

STOCK-BASED PLANS

Summary of stock option plan activity

				Weighted Average	Aggregate
		Weighted Average		Remaining	Intrinsic
	Shares	Exercise Price		Contractual Term	Value
				(In years)
Stock options outstanding at January 1, 2014	965,440	$	64.57
Granted	116,500		144.26
Exercised	—		—
Forfeited	(35,450)		87.45
Expired	—		—
Stock options outstanding at December 31, 2014	1,046,490	$	72.61
Granted	117,000	$	134.24
Exercised	—		—
Forfeited	(77,450)		103.84
Expired	—		—
Stock options outstanding at December 31, 2015	1,086,040	$	77.11
Granted	162,100	$	109.42
Exercised	(3,000)		60.33
Forfeited	(68,500)		122.93
Expired	—		—
Stock options outstanding at December 31, 2016	1,176,640	$	78.87	5.57	$	44,769,359
Stock options exercisable at December 31, 2016	609,740	$	57.89	3.92	$	34,271,449
Stock options vested and expected to vest	1,163,260	$	78.46	5.54	$	44,676,851

Summary of information related to stock options outstanding

								Weighted Average
								Remaining
					Number	Weighted Average		Contractual Term	Number
Range of Exercise Prices					Outstanding	Exercise Price		(In years)	Exercisable
$	46.49	—	$	55.82	47,500	$	52.87	4.5	47,500
$	57.77	—	$	60.33	565,000		57.93	3.9	529,500
$	61.64	—	$	69.75	164,240		66.31	5.2	32,740
$	81.80	—	$	110.50	128,400		97.87	7.0	—
$	112.64	—	$	151.72	271,500		125.61	8.7	—
					1,176,640	$	78.87	5.57	609,740

Summary of Significant Assumptions Used in Black-Scholes Option-Pricing Model

	As of December 31,
	2016			2015			2014
Grant date fair value	$	36.55		$	44.45		$	48.65
Expected life of options (in years)		7.4			7.5			7.5
Risk-free interest rate		1.8	%		2.0	%		2.2	%
Expected volatility		33.1	%		26.1	%		25.7	%
Expected annual dividend per share		—			—			—

Summary of restricted stock activity

	Weighted Average
	Grant Date
	Shares	Fair Value
Restricted stock outstanding at January 1, 2014	122,334	$	75.21
Granted	61,750		126.38
Vested	(11,394)		97.72
Restricted stock outstanding at December 31, 2014	172,690	$	92.02
Granted	81,581	$	121.81
Vested	(7,546)		147.56
Forfeited	(4,169)		101.33
Restricted stock outstanding at December 31, 2015	242,556	$	100.15
Granted	136,198	$	67.80
Vested	(37,670)		83.47
Forfeited	(51,972)		90.14
Restricted stock outstanding at December 31, 2016	289,112	$	88.88