Consolidated Statements of Income (unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues – related party:
Revenues from lease contracts		$ 108,251	$ 84,657	$ 213,577	$ 165,769
Revenues from contracts with customer		26,376	25,888	52,992	50,592
Total revenues – related party		134,627	110,545	266,569	216,361
Costs and expenses:
Cost of revenues from lease contracts (excluding depreciation expense reflected below)	[1]	26,596	20,848	51,114	39,368
Depreciation expense associated with lease contracts		15,849	9,450	31,438	18,480
General and administrative expenses	[2]	4,158	3,863	8,270	7,693
Total costs and expenses		56,377	43,423	110,330	82,573
Operating income		78,250	67,122	156,239	133,788
Other income, net		411	182	793	246
Interest and debt expense, net of capitalized interest	[3]	(14,271)	(8,551)	(26,179)	(16,840)
Income before income tax expense		64,390	58,753	130,853	117,194
Income tax expense		371	310	755	614
Net income		64,019	58,443	130,098	116,580
Less: General partner’s interest in net income		18,077	11,419	34,632	20,886
Limited partners’ interest in net income		$ 45,942	$ 47,024	$ 95,466	$ 95,694
Net income per limited partner common unit – basic and diluted:
Net income per limited partner common unit – basic and diluted (dollars per unit)		$ 0.66	$ 0.69	$ 1.38	$ 1.41
Weighted-average limited partner common units outstanding – basic and diluted:
Weighted-average limited partner common units outstanding – basic and diluted (units)		69,251	68,157	69,250	67,912
Cash distribution declared per unit (dollars per unit)		$ 0.551	$ 0.455	$ 1.0785	$ 0.8825
Services [Member]
Revenues – related party:
Revenues from contracts with customer		$ 26,376	$ 25,888	$ 52,992	$ 50,592
Costs and expenses:
Cost of revenues from contracts with customer (excluding depreciation expense reflected below)	[4]	6,758	6,207	13,541	11,232
Depreciation expense associated with contracts with customer		$ 3,016	$ 3,055	$ 5,967	$ 5,800

[1] Includes cost of revenues from lease contracts (excluding depreciation expense) – related party of $17,075 thousand and $14,369 thousand for the three months ended June 30, 2018 and 2017, respectively, and $35,010 thousand and $28,715 thousand for the six months ended June 30, 2018 and 2017, respectively.

[2] Includes general and administrative expenses – related party of $3,361 thousand and $3,185 thousand for the three months ended June 30, 2018 and 2017, respectively, and $6,722 thousand and $6,371 thousand for the six months ended June 30, 2018 and 2017, respectively.

[3] Includes interest and debt expense – related party of $2,464 thousand and $2,343 thousand for the three months ended June 30, 2018 and 2017, respectively, and $5,310 thousand and $4,450 thousand for the six months ended June 30, 2018 and 2017, respectively.

[4] Includes cost of revenues from contracts with customer (excluding depreciation expense) – related party of $2,018 thousand and $1,767 thousand for the three months ended June 30, 2018 and 2017, respectively, and $4,139 thousand and $3,053 thousand for the six months ended June 30, 2018 and 2017, respectively.