Share-based Awards (Tables)

3 Months Ended

Mar. 31, 2016

Summary of Stock Option Activity

The following table summarizes option activity for the three months ended March 31, 2016:

	Options Outstanding Number of Shares			Weighted  Average  Exercise Price		Weighted  Average Fair Value		Weighted  Average  Remaining  Contractual  Life
Outstanding at December 31, 2015		1,626,582		$	34.87	$	11.94
Granted		161,791		$	71.95	$	20.78
Exercised		(48,840	)	$	23.19	$	9.27
Forfeited		(6,835	)	$	22.51	$	9.61
Outstanding at March 31, 2016		1,732,698		$	38.71	$	12.85		4.86
Exercisable at March 31, 2016		795,005		$	27.80	$	10.23		3.55

Summary of Movement in Non-Vested Share Options

The following table summarizes the movement in non-vested share options for the three months ended March 31, 2016:

	Options Outstanding Number of Shares			Weighted Average Exercise Price		Weighted Average  Fair Value
Non vested outstanding at December 31, 2015		968,853		$	42.14	$	13.69
Granted		161,791		$	71.95	$	20.78
Vested		(187,409	)	$	39.36	$	13.02
Forfeited		(5,542	)	$	21.89	$	9.47
Non vested outstanding at  March 31, 2016		937,693		$	47.96	$	15.07

Weighted Average Fair Values and Assumptions Used

The weighted average fair values and assumptions used were as follows:

	Three Months Ended
	March 31,			March 31,
	2016			2015
Weighted average fair value	$	20.78		$	19.78
Assumptions:
Expected volatility		30	%		30	%
Dividend yield		0	%		0	%
Risk-free interest rate		1.39	%		1.41	%
Expected life	5 years			5 years

RSU and PSU Activity

The following table summarizes RSU and PSU activity for the three months ended March 31, 2016:

	PSU  Outstanding Number of  Shares			PSU Weighted  Average Fair Value		PSU Weighted  Average  Remaining  Contractual  Life		RSU  Outstanding Number of  Shares			RSU Weighted  Average Fair Value		RSU Weighted Average  Remaining  Contractual  Life
Outstanding at December 31, 2015		901,773		$	72.55		2.49		1,067,613		$	48.30		1.48
Granted		233,634		$	71.95				70,087		$	71.95
Shares vested		-			-				(57,328	)	$	25.30
Forfeited		(436	)	$	31.49				(32,947	)	$	47.08
Outstanding at March 31, 2016		1,134,971		$	53.16		1.37		1,047,425		$	51.18		1.41

Schedule of Non-cash Stock Compensation Expense

Non-cash stock compensation expense for the three months ended March 31, 2016 has been allocated as follows:

	Three Months Ended
	March 31,		March 31,
	2016		2015
	(in thousands)
Direct costs	$	5,285	$	3,330
Selling, general and administrative		4,306		2,713
	$	9,591	$	6,043