Equity Incentive Award Plan (Tables)

3 Months Ended

Mar. 31, 2017

Equity Incentive Award Plan

Schedule of stock option activity

	Number of
	Shares	Weighted-
	Subject to	Average
	Option	Exercise Price
Options outstanding, December 31, 2016	265,550	$	22.96
Granted	—		—
Exercised	(163,699)		25.50
Forfeited	—		—
Expired	—		—
Options outstanding, March 31, 2017	101,851	$	19.07

Schedule of unvested shares subject to options

	Number of	Weighted-
	Shares	Average Fair
	Subject to	Value at Grant
	Option	Date
Unvested balance, December 31, 2016	16,323	$	9.99
Granted	—		—
Forfeited	—		—
Vested	(16,323)		9.99
Unvested balance, March 31, 2017	—	$	—

Schedule of restricted awards and RSUs

		Weighted-
	Restricted	Average Fair
	Awards and	Value at Grant
	Units	Date
Unvested balance, December 31, 2016	323,641	$	53.84
Granted	126,846		85.51
Forfeited	(26,321)		62.23
Vested	(117,242)		41.33
Unvested balance, March 31, 2017	306,924	$	69.48

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, 2016	44,835	167,725	113,976	$	54.24
Granted	7,143	49,999	28,571		105.30
Performance adjustment (1)	62,841	—	23,725		—
Forfeited	(5,674)	(16,836)	(11,255)		79.09
Vested	(70,518)	(70,518)	(70,518)		25.89
Unvested balance, March 31, 2017	38,627	130,370	84,499	$	84.49

(1) Includes the annual adjustment for the number of PSAs earned based on our achievement of relative TSR measured versus the MSCI US REIT Index for the applicable performance periods.

Summary of assumptions used to value stock option awards

	Three Months Ended March 31,
	2017		2016
Expected term (in years)	2.81		2.83
Expected volatility	23.33	%	25.29	%
Expected annual dividend(1)	—		—
Risk-free rate	1.60	%	0.97	%

The fair value of the PSAs assumes reinvestment of dividends.