Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block]

The following summarizes the calculation of diluted earnings per share for the years ended December 31, 2018, 2017 and 2016 (in thousands, except per share amounts):

	Year Ended December 31, 2018
	Continuing Operations			Discontinued Operations		Net
Loss	$	(24,328	)	$	—	$	(24,328	)
less: Income attributable to noncontrolling interest	2,421			—		2,421
Loss attributable to SemGroup	$	(26,749	)	$	—	$	(26,749	)
Less: cumulative preferred stock dividends	23,790			—		23,790
Net loss attributable to common shareholders	(50,539		)	—		(50,539		)
Weighted average common stock outstanding	78,313			78,313		78,313
Effect of dilutive securities	—			—		—
Diluted weighted average common stock outstanding	78,313			78,313		78,313
Diluted loss per share	$	(0.65	)	$	—	$	(0.65	)

	Year Ended December 31, 2017
	Continuing Operations			Discontinued Operations		Net
Loss	$	(17,150	)	$	—	$	(17,150	)
less: Income attributable to noncontrolling interest	—			—		—
Loss attributable to SemGroup	$	(17,150	)	$	—	$	(17,150	)
Weighted average common stock outstanding	71,418			71,418		71,418
Effect of dilutive securities	—			—		—
Diluted weighted average common stock outstanding	71,418			71,418		71,418
Diluted loss per share	$	(0.24	)	$	—	$	(0.24	)

	Year Ended December 31, 2016
	Continuing Operations		Discontinued Operations			Net
Income	$	13,263	$	(1	)	$	13,262
less: Income attributable to noncontrolling interest	11,167		—			11,167
Income attributable to SemGroup	$	2,096	$	(1	)	$	2,095
Weighted average common stock outstanding	51,889		51,889			51,889
Effect of dilutive securities	392		392			392
Diluted weighted average common stock outstanding	52,281		52,281			52,281
Diluted earnings per share	$	0.04	$	—		$	0.04

The following summarizes the calculation of basic earnings per share for the years ended December 31, 2018, 2017 and 2016 (in thousands, except per share amounts):

	Year Ended December 31, 2018
	Continuing Operations			Discontinued Operations		Net
Loss	$	(24,328	)	$	—	$	(24,328	)
less: Income attributable to noncontrolling interest	2,421			—		2,421
Loss attributable to SemGroup	$	(26,749	)	$	—	$	(26,749	)
less: cumulative preferred stock dividends	23,790			—		23,790
Net loss attributable to common shareholders	(50,539		)	—		(50,539		)
Weighted average common stock outstanding	78,313			78,313		78,313
Basic loss per share	$	(0.65	)	$	—	$	(0.65	)

	Year Ended December 31, 2017
	Continuing Operations			Discontinued Operations		Net
Loss	$	(17,150	)	$	—	$	(17,150	)
less: Income attributable to noncontrolling interest	—			—		—
Loss attributable to SemGroup	$	(17,150	)	$	—	$	(17,150	)
Weighted average common stock outstanding	71,418			71,418		71,418
Basic loss per share	$	(0.24	)	$	—	$	(0.24	)

	Year Ended December 31, 2016
	Continuing Operations		Discontinued Operations			Net
Income	$	13,263	$	(1	)	$	13,262
less: Income attributable to noncontrolling interest	11,167		—			11,167
Income attributable to SemGroup	$	2,096	$	(1	)	$	2,095
Weighted average common stock outstanding	51,889		51,889			51,889
Basic earnings per share	$	0.04	$	—		$	0.04