Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Weighted-Average Assumptions Used in BSM Model to Calculate Fair Value of Options

The following table sets forth the key weighted-average assumptions used in the BSM Model to calculate the fair value of options:

	Year Ended December 31,
	2018		2017		2016
Expected holding period - years	5.4		5.4		3.6
Expected volatility	27.0%		28.0%		30.2%
Risk-free interest rate	2.8%		2.0%		1.0%
Expected dividend yield		0.0%		0.0%		0.0%

Schedule of Grant Date Fair Value and Stock-based Compensation Expense Allocated

The following table summarizes the grant date fair values of stock options and restricted shares issued during the period as well as the allocation of stock-based compensation expense to Total direct costs, and Selling, general and administrative reported in the consolidated statements of operations:

	Year Ended December 31,
	2018		2017		2016
Weighted average, grant date fair value
Stock options	$	11.51	$	8.54	$	6.91
Restricted shares (RSAs and RSUs)	$	49.38	$	31.90	$	15.08
Stock-based compensation expense    allocated to:
Total direct costs	$	4,132	$	2,128	$	5,555
Selling, general, and administrative		2,367		2,335		4,260
Total stock-based compensation expense	$	6,499	$	4,463	$	9,815

Schedule of Stock Option Activity

The following table sets forth the Company’s stock option activity:

	Year Ended December 31,
	2018					2017					2016
				Weighted Average					Weighted Average					Weighted Average
	Options			Exercise Price		Options			Exercise Price		Shares			Exercise Price
Outstanding - beginning of Period		2,782,868		$	20.73		2,350,166		$	17.57		1,794,709		$	15.42
Granted		584,301		$	37.72		853,896		$	28.67		683,001		$	22.80
Exercised		(169,771	)	$	14.98		(116,787	)	$	15.52		(36,980	)	$	14.50
Forfeited/Expired		(252,358	)	$	23.69		(304,407	)	$	20.55		(90,564	)	$	15.85
Outstanding - end of period		2,945,040		$	24.18		2,782,868		$	20.73		2,350,166		$	17.57
Exercisable - end of period		1,096,116		$	16.01		917,592		$	15.40		647,343		$	15.22

Schedule of Restricted Share Activity

The following table sets forth the Company’s Restricted Share activity:

	Year Ended December 31,
	2018			2017			2016
	Shares/Units			Shares/Units			Shares/Units
Outstanding and unvested - beginning of    period		183,629			59,258			90,697
Granted		300,200			156,000			11,111
Vested		(29,629	)		(29,629	)		(41,069	)
Forfeited		(33,000	)		(2,000	)		(1,481	)
Outstanding and unvested - end of period		421,200			183,629			59,258
Cumulative vested shares - end of period		1,913,916			1,884,287			1,854,658

Schedule of Stock Options Expected To Vest, Stock Options Exercisable, and Unvested Restricted Share Awards Expected To Vest

The following table summarizes information about stock options expected to vest, stock options exercisable, and unvested restricted share awards expected to vest at December 31, 2018:

	Weighted Average						Weighted Average
	Exercise		Stock		Restricted		Remaining
	Price		Options		Shares		Life (Years)
December 31, 2018
Number of stock options expected    to vest	$	24.18		2,945,040		-		4.4
Number of Restricted Shares expected    to vest				-		421,200
Total expected to vest - December 31, 2018				2,945,040		421,200
Total stock options exercisable -    December 31, 2018	$	16.01		1,096,116				3.0
Unrecognized compensation cost -    December 31, 2018 (in thousands)			$	10,021	$	15,734
Weighted average years over which    unrecognized compensation cost will be    recognized				2.7		3.5

Schedule of Aggregate Intrinsic Value of Stock Options Exercised, Fair Values of Awards Vested, and Share Based Liabilities Settled

The following table sets forth the aggregate intrinsic value of stock options exercised, the fair values of awards vested, and share based liabilities settled during the respective periods (in thousands):

	Year Ended December 31,
	2018		2017		2016
Total intrinsic value of stock options    exercised	$	5,326	$	1,619	$	403
Total grant-date fair value of stock    options vested	$	1,417	$	1,317	$	1,384
Total grant-date fair value of    restricted shares vested	$	447	$	447	$	614
Total settlement date fair value of    restricted shares vested	$	1,568	$	1,074	$	1,236
Total share-based liabilities settled	$	-	$	-	$	76