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) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
2013 Equity Incentive Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares)	1,058,297	867,882	584,949
Options, Granted (in shares)	468,875	229,693	317,497
Options, Exercised (in shares)	(155,902)	(29,543)	(23,157)
Options, Cancelled/Expired (in shares)	(2,000)	(9,735)	(11,407)
Ending balance, Options Outstanding (in shares)	1,369,270	1,058,297	867,882
Beginning balance, Weighted average exercise price options outstanding	$ 31.72	$ 27.80	$ 22.87
Weighted average exercise price options outstanding, Granted	50.66	45.78	36.16
Weighted average exercise price options outstanding, Exercised	31.89	25.70	21.30
Weighted average exercise price options outstanding, Cancelled/Expired	37.69	32.14	21.00
Ending balance, Weighted average exercise price options outstanding	38.18	31.72	27.80
Beginning balance, weighted average fair value, options	6.51	5.56	4.10
Weighted average fair value, granted, options	10.32	9.91	8.03
Weighted average fair value, vested, options	6.60	4.96	3.63
Weighted average fair value, cancelled/expired, options	8.77	6.95	3.52
Ending balance, weighted average fair value, options	$ 7.80	$ 6.51	$ 5.56
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)	414,691	394,908	246,785
Number of units, Granted (in shares)	228,576	237,563	230,271
Number of units, Exercised	(163,048)	(122,136)	(54,400)
Number of units, Cancelled/Expired (in shares)	(98,355)	(95,644)	(27,748)
Ending balance, Number of units (in shares)	381,864	414,691	394,908
Beginning balance, Weighted average exercise price units	$ 40.67	$ 33.82	$ 29.13
Weighted average exercise price units, Granted	49.86	45.53	36.71
Weighted average exercise price units, Exercised	40.63	33.26	28.37
Weighted average exercise price units, Cancelled/Expired	39.97	33.92	28.33
Ending balance, Weighted average exercise price units	$ 46.37	$ 40.67	$ 33.82
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)	1,134,811	1,292,899	1,518,717
Number of units, Exercised	(566,771)	(158,088)	(222,499)
Number of units, Cancelled/Expired (in shares)			(3,319)
Ending balance, Number of units (in shares)	568,040	1,134,811	1,292,899
Beginning balance, Weighted average exercise price units	$ 24.06	$ 23.76	$ 23.49
Weighted average exercise price units, Exercised	24.60	21.56	22.02
Weighted average exercise price units, Cancelled/Expired			20.00
Ending balance, Weighted average exercise price units	23.52	24.06	23.76
Beginning balance, Weighted average fair value	3.62	3.68	3.75
Weighted average fair value, Exercised	2.24	4.18	4.18
Weighted average fair value, Cancelled/Expired			3.92
Ending balance, Weighted average fair value	$ 5.00	$ 3.62	$ 3.68
Class RS Units | 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)		39,875	74,625
Number of units, Released from restriction (in shares)		(39,875)	(34,750)
Ending balance, Number of units (in shares)			39,875
Beginning balance, Weighted average exercise price units		$ 22.18	$ 23.49
Weighted average exercise price units, Released from restriction		$ 22.18	25.00
Ending balance, Weighted average exercise price units			$ 22.18