STOCK‑BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2018

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

Stock options, valuation assumptions

The fair value of each stock option award granted is estimated on the date of grant using the Black- Scholes option-pricing model. The fair value of the options was estimated at the date of grant using the following assumptions:

Expected volatility	18		%
Expected dividends	$	—
Expected term (in years)	6.25
Risk free rate	2.23		%

The fair value of the options was estimated at the date of grant using the following assumptions:

Expected volatility	45		%
Expected dividends	$	—
Expected term (in years)	6.25
Risk free rate	1.83		%

The fair value of each option award granted is estimated on the date of grant using the Black- Scholes option-pricing model. The fair value of the options was estimated at the date of grant using the following assumptions:

Expected volatility	55		%
Expected dividends	$	—
Expected term (in years)	5.8
Risk free rate	1.22		%

The fair value of the options was estimated at the date of grant using the following assumptions:

Expected volatility	45		%
Expected dividends	$	—
Expected term (in years)	6.25
Risk free rate	1.35		%

Schedule of stock options, activity

A summary of the stock option activity during the year ended December 31, 2018 is presented below.

	Number of Shares		Weighted Average Exercise Price
Outstanding at January 1, 2018	4,636,353		$	5.20
Granted	—		—
Exercised	(49,912	)	$	4.95
Forfeited	(29,255	)	$	14.00
Expired	—		$	—
Canceled	—		$	—
Outstanding at December 31, 2018	4,557,186		$	5.14
Exercisable at December 31, 2018	3,994,990		$	3.90

Schedule of RSUs, activity

The following table summarizes the restricted stock units activity during the year December 31, 2018:

	Number of Shares		Weighted Average Grant Date Fair Value
Outstanding at January 1, 2018	688,744		$	13.66
Granted	319,250		$	18.49
Vested	(500,360	)	$	13.87
Exercised	—		$	—
Forfeited	(34,129	)	$	15.99
Expired	—		$	—
Canceled	—		$	—
Outstanding at December 31, 2018	473,505		$	16.52

Schedule of performance shares, activity

The following table summarizes the performance stock units activity during the year ended December 31, 2018:

Period Granted	Target Shares Outstanding at Beginning of Year	Target Shares Granted	Target Shares Vested	Target Shares Forfeited	Target Shares Outstanding at End of Year	Weighted Average Grant Date Fair Value per Share
2017	169,635	—	—	—	169,635	$	10.73
2018	—	178,975	—	—	178,975	$	27.51
Total	169,635	178,975	—	—	348,610	$	19.34