Acquisitions and Divestitures - Summary of Unaudited Pro Forma Financial Information (Detail) - Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Business Acquisition [Line Items]
Revenues	$ 80,482	$ 258,547
Net income (loss)	$ 6,845	$ 6,236
Earnings per share:
Basic	$ 0.20	$ 0.24
Diluted	$ 0.20	$ 0.24