CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents	$ 9.5	$ 166.3
Accounts receivable, net	84.1	108.4
Income tax receivable	50.5	37.4
Fair value of derivative contracts	77.5	1.5
Prepaid expenses and other current assets	8.5	11.6
Total Current Assets	230.1	325.2
Property, Plant and Equipment (successful efforts method for oil and gas properties)
Proved properties	9,812.9	9,574.9
Unproved properties	544.2	599.1
Gathering and other	165.5	164.2
Materials and supplies	16.9	15.6
Total Property, Plant and Equipment	10,539.5	10,353.8
Less Accumulated Depreciation, Depletion and Amortization
Exploration and production	5,603.6	5,250.5
Gathering and other	68.5	61.0
Total Accumulated Depreciation, Depletion and Amortization	5,672.1	5,311.5
Net Property, Plant and Equipment	4,867.4	5,042.3
Fair value of derivative contracts	0.8	0.2
Operating lease right-of-use assets, net	52.7	56.8
Other noncurrent assets	85.7	53.3
TOTAL ASSETS	5,236.7	5,477.8
Current Liabilities
Checks outstanding in excess of cash balances	0.0	18.3
Accounts payable and accrued expenses	164.5	227.2
Production and property taxes	10.7	18.9
Interest payable	29.1	31.0
Fair value of derivative contracts	4.7	18.7
Current operating lease lease liabilities	22.6	18.0
Asset retirement obligations	7.1	6.0
Total Current Liabilities	238.7	338.1
Long-term debt	1,590.4	2,015.6
Deferred income taxes	440.0	274.5
Asset retirement obligations	94.8	94.9
Fair value of derivative contracts	6.7	0.5
Operating lease liabilities	35.4	44.8
Other long-term liabilities	32.1	48.8
Commitments and contingencies (Note 11)
EQUITY
Common stock – par value $0.01 per share; 500.0 million shares authorized; 247.2 million and 242.1 million shares issued, respectively	2.5	2.4
Treasury stock – 5.0 million and 4.4 million shares, respectively	(56.7)	(55.4)
Additional paid-in capital	1,466.2	1,456.5
Retained earnings	1,398.6	1,269.6
Accumulated other comprehensive income (loss)	(12.0)	(12.5)
Total Common Shareholders' Equity	2,798.6	2,660.6
TOTAL LIABILITIES AND EQUITY	$ 5,236.7	$ 5,477.8