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)	3 Months Ended
	Mar. 31, 2018 $ / 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	1,369,270
Options, Granted (in shares) | shares	672,549
Ending balance, Options Outstanding (in shares) | shares	2,041,819
Beginning balance, Weighted average exercise price options outstanding	$ 38.18
Weighted average exercise price options outstanding, Granted	34.03
Ending balance, Weighted average exercise price options outstanding	36.81
Beginning balance, weighted average fair value, options	7.80
Weighted average fair value, granted, options	5.63
Ending balance, weighted average fair value, options	$ 7.08
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares) | shares	381,864
Options, Granted (in shares) | shares	340,033
Options, Exercised (in shares) | shares	(101,248)
Options, Cancelled/Expired (in shares) | shares	(31,010)
Ending balance, Options Outstanding (in shares) | shares	589,639
Beginning balance, weighted average fair value, options	$ 46.37
Weighted average fair value, granted, options	35.27
Weighted average fair value, vested, options	48.90
Weighted average fair value, cancelled/expired, options	47.06
Ending balance, weighted average fair value, options	$ 39.50
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	568,040
Number of units, Exercised | shares	(459,472)
Number of units, Cancelled/Expired (in shares) | shares	(1,567)
Ending balance, Number of units (in shares) | shares	107,001
Beginning balance, Weighted average exercise price units	$ 23.52
Weighted average exercise price units, Exercised	23.31
Weighted average exercise price units, Cancelled/Expired	25.00
Ending balance, Weighted average exercise price units	24.40
Beginning balance, Weighted average fair value	5.00
Weighted average fair value, Exercised	4.73
Weighted average fair value, Cancelled/Expired	10.26
Ending balance, Weighted average fair value	$ 6.06