Derivatives (Effect Of Derivative Instruments In The Consolidated Statements Of Operations) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Feb. 08, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts		$ 12,412	$ (29,219)	$ (51,230)	$ (11,365)	$ (11,365)
Predecessor
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts	$ 6,663
Derivatives Not Designated As Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts		12,412	(29,219)	(51,230)	(11,365)
Derivatives Not Designated As Hedging \| Oil
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts		5,134	(28,712)	(50,656)	(16,535)
Derivatives Not Designated As Hedging \| Natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts		$ 7,278	$ (507)	$ (574)	$ 5,170
Derivatives Not Designated As Hedging \| Predecessor
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts	6,663
Derivatives Not Designated As Hedging \| Predecessor \| Oil
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts	4,796
Derivatives Not Designated As Hedging \| Predecessor \| Natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (loss) on derivative contracts	$ 1,867

Alta Mesa Holdings, LP 10-Q