STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2018

STOCK-BASED COMPENSATION

Summary of stock option activity

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic Value
	Shares	Price		Term (years)	(in millions)
Outstanding, December 31, 2017	442,042	$	25.36	1.0	$	17.5
Granted	—		—	—		—
Exercised	(40,133)		19.26
Outstanding and expected to vest at June 30, 2018	401,909	$	25.97	5.0	$	31.4
Exercisable at June 30, 2018	361,374	$	25.73	4.9	$	28.3

Summary of nonvested options

		Weighted
		Average Grant-
Nonvested options	Options	Date Fair Value
January 1, 2018 — Nonvested	81,068	$	49.17
Granted	—		—
Vested	(40,533)		49.17
Forfeited	—		—
June 30, 2018 — Nonvested	40,535	$	49.17

Summary of restricted stock activity

		Weighted
	Number of	average grant
	shares	date fair value
Nonvested stock at December 31, 2017	1,068,392	$	77.19
Granted	209,839		111.13
Vested	(362,996)		74.12
Forfeited	(2,272)		79.52
Nonvested stock at June 30, 2018	912,963	$	87.29