Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Quarterly Financial Data [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	Quarters Ended
	March 31			June 30		September 30		December 31			Total Year
2015:
Revenues	$	10,326		$	11,540	$	6,601	$	5,825		$	34,292
Operating income	608			888		576		187			2,259
Net income	268			839		393		21			1,521
Common Unitholders’ interest in net income (loss)	(48		)	298		59		(327		)	(18		)
Basic net income (loss) per Common Unit	$	(0.17	)	$	0.67	$	0.11	$	(0.68	)	$	(0.09	)
Diluted net income (loss) per Common Unit	$	(0.17	)	$	0.67	$	0.10	$	(0.68	)	$	(0.10	)

	Quarters Ended
	March 31		June 30		September 30		December 31			Total Year
2014:
Revenues	$	13,027	$	14,088	$	14,933	$	13,427		$	55,475
Operating income	706		769		809		159			2,443
Net income (loss)	483		548		513		(245		)	1,299
Common Unitholders’ interest in net income (loss)	253		295		148		(90		)	606
Basic net income (loss) per Common Unit	$	0.76	$	0.92	$	0.44	$	(0.28	)	$	1.77
Diluted net income (loss) per Common Unit	$	0.76	$	0.92	$	0.44	$	(0.28	)	$	1.77