Equity Incentive Plan (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	6 Months Ended
	May 22, 2013	Jun. 30, 2013
Stock options
Equity Incentive Plan
Increase in number of shares of common stock authorized for issuance	3,000,000
Shares of common stock that were available for issuance pursuant to the 2010 Plan	6,000,000	3,622,304
Number of Shares Subject to Option
Options outstanding at the beginning of the period (in shares)		1,017,195
Granted (in shares)		209,268
Forfeited (in shares)		(11,393)
Exercised (in shares)		(33,693)
Options outstanding at the end of the period (in shares)		1,181,377
Weighted Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)		$ 17.25
Granted (in dollars per share)		$ 32.50
Forfeited (in dollars per share)		$ 15.55
Exercised (in dollars per share)		$ 15.59
Options outstanding at the end of the period (in dollars per share)		$ 20.02
Number of Shares Subject to Option
Unvested balance at the beginning of the period (in shares)		730,159
Granted (in shares)		209,268
Forfeited (in shares)		(11,393)
Vested (in shares)		(157,782)
Unvested balance at the end of the period (in shares)		770,252
Weighted Average Fair Value at Grant
Unvested balance at the beginning of the period (in dollars per share)		$ 5.70
Granted (in dollars per share)		$ 10.01
Forfeited (in dollars per share)		$ 4.91
Vested (in dollars per share)		$ 5.86
Unvested balance at the end of the period (in dollars per share)		$ 6.85
Compensation cost not yet recognized
Unearned compensation		$ 4.5
Stock options | Weighted average
Compensation cost not yet recognized
Vesting period		2 years 3 months 18 days
Restricted Awards
Restricted Awards
Unvested balance at the beginning of the period (in shares)		598,695
Granted (in shares)		184,387
Forfeited (in shares)		(10,731)
Vested (in shares)		(196,011)
Unvested balance at the end of the period (in shares)		576,340
Weighted Average Fair Value at Grant Date
Unvested balance at the beginning of the period (in dollars per share)		$ 21.37
Granted (in dollars per share)		$ 32.44
Forfeited (in dollars per share)		$ 23.54
Vested (in dollars per share)		$ 21.56
Unvested balance at the end of the period (in dollars per share)		$ 24.81
Compensation cost not yet recognized
Unearned compensation		12.6
Restricted Awards | Weighted average
Compensation cost not yet recognized
Vesting period		2 years 6 months
Restricted awards
Restricted Awards
Granted (in shares)		179,323
RSUs
Restricted Awards
Granted (in shares)		5,064
Compensation cost not yet recognized
Holder of RSU becomes entitled to the number of shares of common stock for each RSU on applicable vesting date		1
Common Operating Partnership Units
Restricted Awards
Granted (in shares)		25,883
Forfeited (in shares)		(1,491)
Unvested balance at the end of the period (in shares)		7,138
Weighted Average Fair Value at Grant Date
Granted (in dollars per share)		$ 15.98
Total grant date fair value of operating partnership units		0.4
Compensation cost not yet recognized
Unearned compensation		$ 0.1
Vested shares outstanding		17,254
Common Operating Partnership Units | Maximum
Compensation cost not yet recognized
Vesting period		1 year