Partners' Capital, Equity and Incentive Compensation Plans (Summary of Award Activity Under 2010 Equity Incentive Plan and 2013 Equity Incentive Plan and Related Information) (Details) - 6 months ended Jun. 30, 2015 - $ / shares		Total
2013 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Weighted average exercise price units		$ 22.87
Weighted average exercise price units, Granted		36.14
Weighted average exercise price units, Exercised	[1]	$ 21.80
Weighted average exercise price units, Released from restriction	[2]
Weighted average exercise price units, Cancelled/Expired	[3]	$ 21.00
Ending balance, Weighted average exercise price units		27.61
Beginning balance, Weighted average fair value		4.10
Weighted average fair value, Granted		8.02
Weighted average fair value, Exercised	[1]	$ 3.80
Weighted average fair value, Released from restriction	[2]
Weighted average fair value, Cancelled/Expired	[3]	$ 3.52
Ending balance, Weighted average fair value		5.50
Beginning balance, Weighted average exercise price options outstanding		29.13
Weighted average exercise price options outstanding, Granted		35.95
Weighted average exercise price options outstanding, Exercised	[1]	$ 23.26
Weighted average exercise price options outstanding, Released from restriction	[2]
Weighted average exercise price options outstanding, Cancelled/Expired	[3]	$ 23.92
Ending balance, Weighted average exercise price options outstanding		$ 32.70
2013 Equity Incentive Plan [Member] | Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units		584,949
Number of units, granted		312,997
Number of units, Exercised	[1]	(8,843)
Number of units, Released from restriction	[2]
Number of units, Cancelled/Expired	[3]	(8,594)
Ending balance, Number of units		880,509
2013 Equity Incentive Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding		246,785
Options, Granted		186,070
Options, Exercised	[1]	(20,453)
Options, Released from restriction	[2]
Options, Cancelled/Expired	[3]	(9,625)
Ending balance, Options Outstanding		402,777
2010 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Weighted average exercise price units		$ 23.49
Weighted average exercise price units, Granted
Weighted average exercise price units, Exercised	[1]	$ 20.62
Weighted average exercise price units, Released from restriction	[2]
Weighted average exercise price units, Cancelled/Expired	[3]
Ending balance, Weighted average exercise price units		$ 23.58
Beginning balance, Weighted average fair value		$ 3.75
Weighted average fair value, Granted
Weighted average fair value, Exercised	[1]	$ 4.74
Weighted average fair value, Released from restriction	[2]
Weighted average fair value, Cancelled/Expired	[3]
Ending balance, Weighted average fair value		$ 3.72
Beginning balance, Weighted average exercise price options outstanding		$ 23.49
Weighted average exercise price options outstanding, Granted
Weighted average exercise price options outstanding, Exercised	[1]
Weighted average exercise price options outstanding, Released from restriction	[2]	$ 25.00
Weighted average exercise price options outstanding, Cancelled/Expired	[3]
Ending balance, Weighted average exercise price options outstanding		$ 23.03
Restricted Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units surrendered		9,625
Class O Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, Number of units		600,000
Class O Units [Member] | 2010 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units		1,518,717
Number of units, granted
Number of units, Exercised	[1]	(46,170)
Number of units, Released from restriction	[2]
Number of units, Cancelled/Expired	[3]
Ending balance, Number of units		1,472,547
Class RS Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, Number of units		100,000
Class RS Units [Member] | 2010 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding		74,625
Options, Granted
Options, Exercised	[1]
Options, Released from restriction	[2]	(17,375)
Options, Cancelled/Expired	[3]
Ending balance, Options Outstanding		57,250

[1] This represents the Class A common stock that has been released from restriction and which was not surrendered by the holder to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock.

[2] This represents Class RS units that upon vesting have converted to Operating Partnership units.

[3] Includes 9,625 restricted Class A common stock surrendered by certain employees to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock.