Segment Reporting - Information Concerning Business Activities (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			2
Number of operating segments | segment			2
Segment Reporting Information [Line Items]
Revenues	$ 450,307,000	$ 467,891,000	$ 1,379,908,000	$ 1,307,564,000
Segment operating earnings	303,000	2,239,000	4,913,000	7,614,000
Depreciation and amortization	4,393,000	2,340,000	12,266,000	7,014,000
Inventory liquidation (losses) gains	(2,100,000)
Property and equipment acquired under finance leases		1,200,000		1,200,000
Tractors and Tank Storage and Throughput Arrangements
Segment Reporting Information [Line Items]
Property and equipment additions			4,100,000
Leasehold Improvements
Segment Reporting Information [Line Items]
Property and equipment additions				13,000
Marketing
Segment Reporting Information [Line Items]
Revenues	434,609,000	453,626,000	1,331,410,000	1,266,055,000
Inventory liquidation (losses) gains		100,000	1,500,000	2,500,000
Transportation
Segment Reporting Information [Line Items]
Revenues	15,698,000	14,265,000	48,498,000	41,509,000
Reporting Segments
Segment Reporting Information [Line Items]
Revenues	450,307,000	467,891,000	1,379,908,000	1,307,564,000
Segment operating earnings	3,042,000	3,772,000	12,918,000	13,714,000
Depreciation and amortization	4,393,000	2,340,000	12,266,000	7,014,000
Property and equipment additions	12,304,000	5,028,000	25,425,000	7,756,000
Reporting Segments | Marketing
Segment Reporting Information [Line Items]
Revenues	434,609,000	453,626,000	1,331,410,000	1,266,055,000
Segment operating earnings	2,888,000	2,982,000	10,948,000	11,712,000
Depreciation and amortization	2,214,000	1,277,000	6,640,000	4,110,000
Property and equipment additions	3,894,000	612,000	6,896,000	1,682,000
Reporting Segments | Transportation
Segment Reporting Information [Line Items]
Revenues	15,698,000	14,265,000	48,498,000	41,509,000
Segment operating earnings	154,000	790,000	1,970,000	2,002,000
Depreciation and amortization	2,179,000	1,063,000	5,626,000	2,904,000
Property and equipment additions	8,410,000	4,416,000	18,529,000	6,061,000
Reporting Segments | Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Segment operating earnings	0	0	0	0
Depreciation and amortization	0	0	0	0
Property and equipment additions	0	0	0	13,000
Intersegment
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 0	$ 0	$ 0