CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 97.1	$ 0.0
Accounts receivable, net	93.5	104.3
Income tax receivable	70.8	75.9
Fair value of derivative contracts	2.7	87.5
Prepaid expenses	7.1	12.7
Other current assets	0.2	0.2
Total Current Assets	271.4	280.6
Property, Plant and Equipment (successful efforts method for oil and gas properties)
Proved properties	9,316.0	9,096.9
Unproved properties	706.6	705.5
Gathering and other	169.1	167.7
Materials and supplies	20.9	29.9
Total Property, Plant and Equipment	10,212.6	10,000.0
Less Accumulated Depreciation, Depletion and Amortization
Exploration and production	5,050.9	4,882.4
Gathering and other	58.4	58.1
Total Accumulated Depreciation, Depletion and Amortization	5,109.3	4,940.5
Net Property, Plant and Equipment	5,103.3	5,059.5
Fair value of derivative contracts	15.2	35.4
Operating lease right-of-use assets, net	60.2	0.0
Other noncurrent assets	54.2	49.6
Noncurrent assets held for sale	0.0	692.7
TOTAL ASSETS	5,504.3	6,117.8
Current Liabilities
Checks outstanding in excess of cash balances	5.3	14.6
Accounts payable and accrued expenses	227.9	258.1
Production and property taxes	15.9	24.1
Current portion of long term debt	51.7	0.0
Interest payable	32.5	32.4
Fair value of derivative contracts	17.6	0.0
Current operating lease lease liabilities	18.8	0.0
Asset retirement obligations	6.8	5.1
Total Current Liabilities	376.5	334.3
Long-term debt	2,028.1	2,507.1
Deferred income taxes	181.4	269.2
Asset retirement obligations	94.6	96.9
Fair value of derivative contracts	0.9	0.7
Operating lease liabilities	47.9	0.0
Other long-term liabilities	85.6	97.4
Other long-term liabilities held for sale	0.0	61.3
Commitments and contingencies (Note 11)
EQUITY
Common stock – par value $0.01 per share; 500.0 million shares authorized; 242.0 million and 239.8 million shares issued, respectively	2.4	2.4
Treasury stock – 4.1 million and 3.1 million shares, respectively	(53.6)	(45.6)
Additional paid-in capital	1,446.3	1,431.9
Retained earnings	1,308.6	1,376.5
Accumulated other comprehensive income (loss)	(14.4)	(14.3)
Total Common Shareholders' Equity	2,689.3	2,750.9
TOTAL LIABILITIES AND EQUITY	$ 5,504.3	$ 6,117.8