Permanent Equity (Details)	6 Months Ended
	Jun. 30, 2012
Schedule of unrestricted common stock, activity
Balance at beginning of the period	10,132,497
Shares issued in connection with the redemption of Operating LLC units	186,339
Vesting of shares	239,259
Shares withheld for employee taxes	(1,780)
Balance at end of the period	10,556,315