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)	9 Months Ended
	Sep. 30, 2017 $ / shares shares
2013 Equity Incentive Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares) | shares	1,058,297
Options, Granted (in shares) | shares	468,875
Options, Exercised (in shares) | shares	(154,965)
Options, Cancelled/Expired (in shares) | shares	(2,000)
Ending balance, Options Outstanding (in shares) | shares	1,370,207
Beginning balance, Weighted average exercise price options outstanding	$ 31.72
Weighted average exercise price options outstanding, Granted	50.66
Weighted average exercise price options outstanding, Exercised	31.93
Weighted average exercise price options outstanding, Cancelled/Expired	37.69
Ending balance, Weighted average exercise price options outstanding	38.17
Beginning balance, weighted average fair value, options	6.51
Weighted average fair value, granted, options	10.32
Weighted average fair value, vested, options	6.61
Weighted average fair value, cancelled/expired, options	8.77
Ending balance, weighted average fair value, options	$ 7.80
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares) | shares	414,691
Options, Granted (in shares) | shares	228,576
Options, Exercised (in shares) | shares	(130,368)
Options, Cancelled/Expired (in shares) | shares	(69,903)
Ending balance, Options Outstanding (in shares) | shares	442,996
Beginning balance, weighted average fair value, options	$ 40.67
Weighted average fair value, granted, options	50.25
Weighted average fair value, vested, options	41.22
Weighted average fair value, cancelled/expired, options	40.49
Ending balance, weighted average fair value, options	$ 45.48
Class O Units | 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares) | shares	1,134,811
Number of units, Exercised | shares	(552,146)
Ending balance, Number of units (in shares) | shares	582,665
Beginning balance, Weighted average exercise price units	$ 24.06
Weighted average exercise price units, Exercised	24.66
Ending balance, Weighted average exercise price units	23.49
Beginning balance, Weighted average fair value	3.62
Weighted average fair value, Exercised	2.14
Ending balance, Weighted average fair value	$ 5.03