Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Activities by Segment [Abstract]
Revenues	$ 831,474	$ 777,538	$ 1,708,963	$ 1,441,384
Segment Operating Earnings	11,028	7,936	22,642	18,820
Depreciation Depletion and Amortization	5,026	3,792	9,189	7,108
Property and Equipment Additions	16,388	15,237	31,610	30,262
Segment operating earnings [Abstract]
Segment operating earnings (loss)	11,028	7,936	22,642	18,820
General and administrative	(2,465)	(2,488)	(4,697)	(4,597)
Operating earnings	8,563	5,448	17,945	14,223
Interest income	21	43	42	91
Interest expense	(2)	(7)	(3)	(7)
Earnings from continuing operations before income taxes and discontinued operations	8,582	5,484	17,984	14,307
Identifiable assets by segment [Abstract]
Assets	344,035		344,035		378,840
Marketing [Member]
Activities by Segment [Abstract]
Revenues	810,722	755,648	1,668,152	1,400,664
Segment Operating Earnings	9,327	5,174	17,485	12,020
Depreciation Depletion and Amortization	1,438	811	2,729	1,540
Property and Equipment Additions	3,207	5,196	7,406	8,684
Segment operating earnings [Abstract]
Segment operating earnings (loss)	9,327	5,174	17,485	12,020
Identifiable assets by segment [Abstract]
Assets	230,451		230,451		266,063
Marketing [Member] | Crude Oil [Member]
Activities by Segment [Abstract]
Revenues	809,358	754,288	1,665,204	1,397,971
Segment Operating Earnings	8,837	4,613	16,602	10,940
Depreciation Depletion and Amortization	1,438	810	2,728	1,538
Property and Equipment Additions	3,207	5,168	7,406	8,628
Segment operating earnings [Abstract]
Segment operating earnings (loss)	8,837	4,613	16,602	10,940
Identifiable assets by segment [Abstract]
Assets	221,137		221,137		253,817
Marketing [Member] | Natural Gas [Member]
Activities by Segment [Abstract]
Revenues	1,364	1,360	2,948	2,693
Segment Operating Earnings	490	561	883	1,080
Depreciation Depletion and Amortization	0	1	1	2
Property and Equipment Additions	0	28	0	56
Segment operating earnings [Abstract]
Segment operating earnings (loss)	490	561	883	1,080
Identifiable assets by segment [Abstract]
Assets	9,314		9,314		12,246
Transportation [Member]
Activities by Segment [Abstract]
Revenues	17,128	18,076	33,396	34,149
Segment Operating Earnings	2,258	2,933	5,312	4,925
Depreciation Depletion and Amortization	1,361	1,029	2,612	1,874
Property and Equipment Additions	6,056	5,001	10,744	9,128
Segment operating earnings [Abstract]
Segment operating earnings (loss)	2,258	2,933	5,312	4,925
Identifiable assets by segment [Abstract]
Assets	37,189		37,189		27,221
Oil and Gas [Member]
Activities by Segment [Abstract]
Revenues	3,624	3,814	7,415	6,571
Segment Operating Earnings	(557)	(171)	(155)	1,875
Depreciation Depletion and Amortization	2,227	1,952	3,848	3,694
Property and Equipment Additions	7,125	5,040	13,460	12,395
Segment operating earnings [Abstract]
Segment operating earnings (loss)	(557)	(171)	(155)	1,875
Identifiable assets by segment [Abstract]
Assets	37,148		37,148		29,105
Other [Member]
Identifiable assets by segment [Abstract]
Assets	$ 39,247		$ 39,247		$ 56,451