Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details) (USD $)	3 Months Ended			9 Months Ended	0 Months Ended	9 Months Ended	3 Months Ended			9 Months Ended
	Sep. 30, 2014 item	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2014 security item	Oct. 07, 2014 Subsequent Event [Member]	Sep. 30, 2014 Subsequent Event [Member]	Jun. 30, 2014 Class O LTIP Holders [Member]	Sep. 30, 2014 Class O Units [Member]	Sep. 30, 2014 Class RS Units [Member]	Sep. 30, 2014 Chief Executive Officer [Member]	Sep. 30, 2014 Restricted Class A Common Stock [Member]	Sep. 30, 2014 Options to purchase Class A common stock [Member]	Sep. 30, 2014 2013 Equity Incentive Plan [Member]
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding				3
Authorized shares to be issued under the plan													1,750,000
Number of votes per share	50			50
Percentage of operating partnership unit exchanged										2.00%
Nonvested awards outstanding								800,000	100,000		200,000	600,000
Equity based compensation expense unrecognized	$ 7,300,000			$ 7,300,000
Equity based compensation expense vesting period				4 years
Equity based compensation awards intrinsic value	20,900,000			20,900,000
Aggregate distribution made to stockholders and partners	$ 10,700,000	$ 10,700,000	$ 9,000,000		$ 10,500,000		$ 200,000
Dividend paid to common stockholders	$ 0.29	$ 0.29	$ 0.24
Partnership distribution per unit	$ 0.29	$ 0.29	$ 0.24		$ 0.29
Dividends payable, date paid	Jul. 08, 2014	Apr. 08, 2014			Oct. 07, 2014	Oct. 07, 2014
Cash dividend per common share					$ 0.29
Dividends payable, date of record						Sep. 19, 2014