Equity Incentive Award Plan (Tables)

12 Months Ended

Dec. 31, 2016

Equity Incentive Award Plan

Schedule of stock option activity

	Number of Shares Subject to Option	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Options outstanding, December 31, 2013	1,133,915	$	19.89	7.6 years	$14.0 million
Granted	—		—
Exercised	(307,022)		16.10		$5.6 million
Forfeited	(64,851)		25.83
Expired	(3,947)		15.80
Options outstanding, December 31, 2014	758,095	$	20.94	6.7 years	$13.7 million
Granted	—		—
Exercised	(410,322)		20.15		$12.0 million
Forfeited	(7,281)		27.53
Expired	(282)		15.23
Options outstanding, December 31, 2015	340,210	$	21.77	5.8 years	$11.9 million
Granted	—		—
Exercised	(74,660)		17.27		$3.8 million
Forfeited	—		—
Expired	—		—
Options outstanding, December 31, 2016	265,550	$	22.96	5.0 years	$15.0 million
Exercisable at December 31,
2014	474,132	$	18.78	6.4 years	$9.6 million
2015	234,943	$	18.47	5.4 years	$9.0 million
2016	249,227	$	22.29	4.9 years	$14.2 million

Schedule of unvested shares subject to options

	Number of Shares Subject to Option	Weighted Average Fair Value at Grant Date
Unvested balance, December 31, 2013	635,739	$	7.10
Granted	—		—
Forfeited	(64,851)		8.03
Vested	(286,924)		6.25
Unvested balance, December 31, 2014	283,964	$	7.75
Granted	—		—
Forfeited	(7,281)		8.48
Vested	(171,416)		6.86
Unvested balance, December 31, 2015	105,267	$	9.13
Granted	—		—
Forfeited	—		—
Vested	(88,944)		8.97
Unvested balance, December 31, 2016	16,323	$	9.99

Schedule of restricted awards and RSUs

	Restricted Awards and Units	Weighted Average Fair Value at Grant Date
Unvested balance, December 31, 2013	495,151	$	25.08
Granted	216,175		31.51
Forfeited	(109,798)		27.64
Vested	(207,512)		22.79
Unvested balance, December 31, 2014	394,016	$	29.10
Granted	187,644		47.41
Forfeited	(34,788)		36.06
Vested	(169,260)		26.96
Unvested balance, December 31, 2015	377,612	$	38.51
Granted	182,628		66.69
Forfeited	(37,383)		53.87
Vested	(199,216)		36.57
Unvested balance, December 31, 2016	323,641	$	53.84

Schedule of unvested PSAs and their weighted-average fair value at the date of grant

				Weighted-
				Average Fair
	Performance-Based Restricted Stock Awards			Value at Grant
	Minimum	Maximum	Target	Date
Unvested balance, December 31, 2013	—	—	—	$	—
Granted	—	91,335	60,889		25.89
Performance adjustment	—	—	—		—
Forfeited	—	(5,484)	(3,656)		25.89
Vested	—	—	—		25.89
Unvested balance, December 31, 2014	—	85,851	57,233	$	25.89
Granted	11,222	78,553	44,886		61.22
Performance adjustment	9,981	(7,190)	(1,465)		—
Forfeited	(1,018)	(13,657)	(8,572)		43.38
Vested	(594)	(594)	(594)		25.89
Unvested balance, December 31, 2015	19,591	142,963	91,488	$	42.78
Granted	11,796	82,572	47,184		84.78
Performance adjustment	29,256	—	11,893		—
Forfeited	(13,474)	(55,916)	(34,695)		69.12
Vested	(1,894)	(1,894)	(1,894)		42.17
Unvested balance, December 31, 2016	45,275	167,725	113,976	$	54.24

Summary of assumptions used to value performance stock awards

	2016		2015			2014
Expected term (in years)	2.83			2.83		2.83
Expected volatility	25.29	%		25.51	%	32.98	%
Expected annual dividend(1)	—			—		—
Risk-free rate	0.97	%		1.02	%	0.64	%
______________________
(1) The fair value of the PSAs assumes reinvestment of dividends.