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, 2017 $ / shares shares
2013 Equity Incentive Plan [Member] | Options [Member]
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	(24,875)
Options, Cancelled/Expired (in shares) | shares	(2,000)
Ending balance, Options Outstanding (in shares) | shares	1,500,297
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	25.33
Weighted average exercise price options outstanding, Cancelled/Expired	37.69
Ending balance, Weighted average exercise price options outstanding	37.74
Beginning balance, weighted average fair value, options	6.51
Weighted average fair value, granted, options	10.32
Weighted average fair value, vested, options	4.87
Weighted average fair value, cancelled/expired, options	8.77
Ending balance, weighted average fair value, options	$ 7.72
2013 Equity Incentive Plan [Member] | Restricted Stock [Member]
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	227,188
Options, Exercised (in shares) | shares	(110,343)
Options, Cancelled/Expired (in shares) | shares	(54,263)
Ending balance, Options Outstanding (in shares) | shares	477,273
Beginning balance, weighted average fair value, options	$ 40.67
Weighted average fair value, granted, options	50.66
Weighted average fair value, vested, options	41.96
Weighted average fair value, cancelled/expired, options	41.33
Ending balance, weighted average fair value, options	$ 45.05
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 (in shares) | shares	1,134,811
Number of units, Exercised | shares	(48,276)
Ending balance, Number of units (in shares) | shares	1,086,535
Beginning balance, Weighted average exercise price units	$ 24.06
Weighted average exercise price units, Exercised	21.09
Ending balance, Weighted average exercise price units	24.19
Beginning balance, Weighted average fair value	3.62
Weighted average fair value, Exercised	5.54
Ending balance, Weighted average fair value	$ 3.53