6.	SHARE-BASED COMPENSATION EXPENSE

The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2018:

	Number of Shares			Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Outstanding, January 1, 2018		306		$	16.28
Granted		0			0
Exercised		(101	)		19.16
Forfeited/expired		(1	)		20.94
Outstanding, September 30, 2018		204		$	14.83		2.75	$	4,536
Exercisable, September 30, 2018		159		$	13.12		2.32	$	3,815
Vested and expected to vest at September 30, 2018		203		$	14.81		2.74	$	4,525

The Company recorded compensation expense of $65 and $246 in the accompanying consolidated statements of operations during the three and nine months ended September 30, 2018, respectively, for stock option awards. During the three and nine months ended September 30, 2017, the Company recorded compensation expense of $204 and $679, respectively. The total intrinsic value of stock options exercised during the three and nine months ended September 30, 2018 was $336 and $2,615, respectively, and $2,847 and $8,269 for the comparable periods of 2017, respectively.

The Company has issued restricted stock to employees generally with vesting terms ranging from two to four years. The fair value is equal to the market price of the Company’s common stock on the date of grant. Expense for restricted stock is amortized ratably over the vesting period. The following table summarizes the restricted stock activity for the nine months ended September 30, 2018:

	Number of Shares			Weighted-Average Grant-Date Fair Value		Aggregate Intrinsic Value
Nonvested, January 1, 2018		232		$	32.96
Granted		121			51.90
Vested		(115	)		25.38
Forfeited		(6	)		40.79
Nonvested, September 30, 2018		232		$	46.34	$	8,625

Additionally, the Company grants performance-based restricted stock units. The performance-based units have performance conditions and service-based vesting conditions. Each vesting tranche is treated as an individual award and the compensation expense is recognized on a straight-line basis over the requisite service period for each tranche. The requisite service period is a combination of the performance period and the subsequent vesting period based on continued service. The level of achievement of such goals may cause the actual amount of units that ultimately vest to range from 0% to 200% of the original units granted. The Company recognizes expense ratably over the vesting period for performance-based restricted stock units when it is probable that the performance criteria specified will be achieved. The fair value is equal to the market price of the Company’s common stock on the date of grant.

The following table summarizes the restricted stock unit activity for the nine months ended September 30, 2018:

	Number of Restricted Stock Units			Weighted-Average Grant-Date Fair Value		Aggregate Intrinsic Value
Nonvested, January 1, 2018		232		$	29.20
Granted		83			31.30
Vested		0			0
Forfeited		(2	)		29.70
Nonvested, September 30, 2018		313		$	29.75	$	11,599

The Company recorded compensation expense of $2,253 and $6,499 in the accompanying consolidated statements of operations for the three and nine months ended September 30, 2018, respectively, and $2,421 and $6,520 for the comparable periods of 2017, respectively, in connection with the issuance of the restricted stock and restricted stock units. As of September 30, 2018, the Company expects 228 shares of restricted stock and 308 restricted stock units to vest.

As of September 30, 2018, there was $11,102 of total unrecognized compensation expense related to unvested share-based compensation arrangements, which is expected to be recognized over a weighted-average period of 1.0 year. The total unrecognized compensation expense will be fully charged to expense through the third quarter of 2021.