Acquisitions - Asset Acquisitions - Additional Information (Details) - USD ($) $ in Millions	Jan. 11, 2019	Aug. 31, 2018
Gunflint Acquisition
Business Acquisition [Line Items]
Percentage of non-operated working interest acquired	9.60%
Purchase price	$ 29.6
Customary purchase price adjustments	$ 27.9
Whistler Energy II, LLC
Business Acquisition [Line Items]
Purchase price		$ 52.6
Business acquisition purchase price net		14.8
Available cash acquired		37.8
Business combination cash collateral		30.8
Business combination cash on hand for working capital		$ 7.0

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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