Stockholders' Equity and Partners' Capital - Restricted Common Stock Activity (Details) - Restricted Common Stock	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Restricted Common Stock
Balance as of beginning of period (in shares)	463,050
Granted (in shares)	221,076
Vested (in shares)	(135,213)
Forfeited (in shares)	(21,378)
Balance as of end of period (in shares)	527,535
Weighted Average Grant Date Fair Value
Balance as of beginning of period (in usd per share) | $ / shares	$ 20.90
Granted (in usd per share) | $ / shares	26.57
Vested (in usd per share) | $ / shares	21.89
Forfeited (in usd per share) | $ / shares	22.70
Balance as of end of period (in usd per share) | $ / shares	$ 22.88