Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial data

The following tables summarize quarterly financial data for the years ended December 31, 2017 and 2016 (in thousands, except per unit amounts):

	2017 Quarter Ended
	March 31		June 30		September 30		December 31
Operating revenues – related party	$	105,816	$	110,545	$	109,340	$	126,304
Gross profit (a)	70,496		70,985		70,749		78,926
Operating income	66,666		67,122		66,347		74,895
Net income	58,137		58,443		57,589		64,264
Net income attributable to partners	58,137		58,443		57,589		64,264
Limited partners’ interest in net income	48,670		47,024		44,552		49,074
Net income per limited partner unit – basic and diluted:
Common units	0.72		0.69		0.65		0.71

	2016 Quarter Ended
	March 31		June 30		September 30		December 31
Operating revenues – related party	$	78,767	$	87,664	$	92,040	$	104,148
Gross profit (a)	42,969		51,757		56,632		69,181
Operating income	38,604		48,042		52,538		65,390
Net income	35,780		44,545		48,707		59,799
Net income attributable to partners	43,298		49,447		51,709		59,799
Limited partners’ interest in net income	39,794		44,234		45,075		51,597
Net income per limited partner unit – basic and diluted:
Common units	0.61		0.67		0.77		0.77
Subordinated units	0.61		0.67		0.29		—
(a) Gross profit is calculated as operating revenues – related party less cost of revenues (excluding depreciation expense) and depreciation expense.