Segment Information (Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 468,039	$ 607,396
Operating Income (Loss)	21,438	17,561
Nonoperating Income (Expense)	(7,170)	(3,947)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	14,268	13,614
Depreciation and amortization	7,144	5,892
Payments to Acquire Productive Assets	6,241	26,644
Assets	487,326	550,643	$ 500,951
Logistics Segment [Member]
Segment Reporting Information [Line Items]
Revenues: Affiliate	40,916	34,775
Revenues: Third-party	690	623
Total revenues	41,606	35,398
Operating Income (Loss)	13,930	11,352
Depreciation and amortization	5,961	4,815
Payments to Acquire Productive Assets	5,869	23,597
Assets	308,490	284,062
Wholesale Segment [Member]
Segment Reporting Information [Line Items]
Revenues: Affiliate	108,541	143,474
Revenues: Third-party	317,892	428,524
Total revenues	426,433	571,998
Operating Income (Loss)	9,953	8,989
Depreciation and amortization	1,183	1,077
Payments to Acquire Productive Assets	372	3,047
Assets	151,323	180,085
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	(2,445)	(2,780)
Assets	$ 27,513	$ 86,496