Business Segments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	$ 12,200,000	$ 5,200,000	$ 19,900,000	$ 8,500,000
Revenues from external customers	733,200,000	758,300,000	2,096,700,000	2,357,500,000
Lease operating expenses
Lease operating expenses and taxes other than income	137,200,000	160,000,000.0	430,600,000	491,700,000
Repair and maintenance	15,300,000	16,900,000	42,000,000.0	45,100,000
Workovers	31,900,000	46,000,000.0	132,400,000	180,000,000.0
Total lease operating expenses	184,353,000	222,886,000	604,986,000	716,778,000
Severance and ad valorem taxes	12,288,000	10,503,000	31,766,000	31,006,000
Transportation, gathering and processing	48,146,000	47,438,000	151,067,000	157,461,000
Costs of purchased natural gas	0	0	0	3,147,000
Selling and general expenses	30,900,000	24,900,000	98,700,000	78,900,000
Exploration Expenses
Geological and geophysical	20,300,000	12,800,000	24,700,000	22,300,000
Dry holes and previously suspended exploration costs	800,000	11,200,000	100,000	69,600,000
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	11,400,000	7,300,000	32,600,000	26,500,000
Total exploration expenses	32,502,000	31,284,000	57,389,000	118,390,000
Depreciation, depletion and amortization	283,500,000	223,600,000	736,900,000	650,300,000
Impairment of assets	115,002,000	0	115,002,000	34,528,000
Accretion of asset retirement obligations	14,676,000	13,241,000	43,153,000	39,068,000
Other operating expenses	5,900,000	5,500,000	13,400,000	10,500,000
Interest Income	(3,100,000)	(3,900,000)	(10,000,000.0)	(30,200,000)
Interest expense, net of capitalization	24,726,000	21,258,000	73,302,000	62,265,000
Income tax expense
Current income tax expense (benefit)	2,100,000	11,000,000.0	14,600,000	19,800,000
Deferred income tax expense (benefit)	2,100,000	(8,900,000)	23,300,000	45,100,000
Total income tax expense (benefit)	4,200,000	2,100,000	37,900,000	64,900,000
Other segment costs (income)	(11,600,000)	8,300,000	26,800,000	(1,600,000)
Net income (loss) including noncontrolling interest	(8,316,000)	151,112,000	116,226,000	422,032,000
Additions to property, plant, equipment	181,000,000.0	172,200,000	817,000,000.0	695,200,000
Total assets at quarter-end	9,732,762,000	9,716,400,000	9,732,762,000	9,716,400,000	$ 9,667,479,000
Minimum
Exploration Expenses
Interest expense, net of capitalization		21,300,000
Income tax expense
Net income (loss) including noncontrolling interest		151,100,000
Maximum
Lease operating expenses
Transportation, gathering and processing		47,500,000
Revenue from production
Segment Reporting Information [Line Items]
Revenue from production	721,000,000.0	753,100,000	2,076,800,000	2,345,300,000
Sales of purchased natural gas
Segment Reporting Information [Line Items]
Revenue from production				3,700,000
Operating Segments
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	800,000	1,000,000.0	4,900,000	4,300,000
Revenues from external customers	721,800,000	754,100,000	2,081,700,000	2,353,300,000
Lease operating expenses
Lease operating expenses and taxes other than income	137,200,000	160,000,000.0	430,600,000	491,700,000
Repair and maintenance	15,300,000	16,900,000	42,000,000.0	45,100,000
Workovers	31,900,000	46,000,000.0	132,400,000	180,000,000.0
Total lease operating expenses	184,400,000	222,900,000	605,000,000.0	716,800,000
Severance and ad valorem taxes	12,300,000	10,500,000	31,800,000	31,000,000.0
Transportation, gathering and processing	48,100,000	47,500,000	151,100,000	157,500,000
Costs of purchased natural gas				3,100,000
Selling and general expenses	9,500,000	4,900,000	32,500,000	13,900,000
Exploration Expenses
Geological and geophysical	20,300,000	12,800,000	24,700,000	22,300,000
Dry holes and previously suspended exploration costs	800,000	11,200,000	100,000	69,600,000
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	11,400,000	7,300,000	32,600,000	26,500,000
Total exploration expenses	32,500,000	31,300,000	57,400,000	118,400,000
Depreciation, depletion and amortization	281,400,000	222,100,000	730,700,000	643,300,000
Impairment of assets		0	115,000,000.0	34,500,000
Accretion of asset retirement obligations	14,600,000	13,200,000	43,100,000	39,000,000.0
Other operating expenses	6,000,000.0	5,400,000	10,400,000	10,700,000
Interest Income	(400,000)	(800,000)	(1,300,000)	(21,600,000)
Interest expense, net of capitalization	100,000	300,000	200,000	600,000
Income tax expense
Current income tax expense (benefit)	(700,000)	8,900,000	14,700,000	13,600,000
Deferred income tax expense (benefit)	7,300,000	600,000	48,700,000	73,900,000
Total income tax expense (benefit)	6,600,000	9,500,000	63,400,000	87,500,000
Other segment costs (income)	900,000	1,900,000	3,700,000	5,600,000
Net income (loss) including noncontrolling interest	10,800,000	185,400,000	238,700,000	513,000,000.0
Additions to property, plant, equipment	178,700,000	164,200,000	807,800,000	678,800,000
Total assets at quarter-end	9,241,700,000	9,397,900,000	9,241,700,000	9,397,900,000
Operating Segments | United States
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	300,000	500,000	3,600,000	3,100,000
Revenues from external customers	613,700,000	597,000,000.0	1,676,700,000	1,936,100,000
Lease operating expenses
Lease operating expenses and taxes other than income	95,600,000	108,000,000.0	295,900,000	348,600,000
Repair and maintenance	13,900,000	15,100,000	38,000,000.0	41,900,000
Workovers	31,800,000	45,700,000	131,500,000	177,200,000
Total lease operating expenses	141,300,000	168,800,000	465,400,000	567,700,000
Severance and ad valorem taxes	11,900,000	10,100,000	30,700,000	29,900,000
Transportation, gathering and processing	23,300,000	26,300,000	82,400,000	97,100,000
Costs of purchased natural gas				0
Selling and general expenses	1,900,000	(1,700,000)	8,700,000	(5,200,000)
Exploration Expenses
Geological and geophysical	19,100,000	9,900,000	23,000,000.0	13,500,000
Dry holes and previously suspended exploration costs	(100,000)	10,800,000	(900,000)	67,900,000
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	3,500,000	2,500,000	9,800,000	9,600,000
Total exploration expenses	22,500,000	23,200,000	31,900,000	91,000,000.0
Depreciation, depletion and amortization	242,100,000	179,300,000	619,700,000	528,300,000
Impairment of assets		0	115,000,000.0	34,500,000
Accretion of asset retirement obligations	11,800,000	10,900,000	34,800,000	32,000,000.0
Other operating expenses	5,700,000	4,800,000	9,700,000	8,000,000.0
Interest Income	(400,000)	(800,000)	(1,300,000)	(21,600,000)
Interest expense, net of capitalization	0	300,000	0	300,000
Income tax expense
Current income tax expense (benefit)	1,000,000.0	800,000	2,200,000	2,900,000
Deferred income tax expense (benefit)	7,900,000	34,400,000	51,600,000	106,900,000
Total income tax expense (benefit)	8,900,000	35,200,000	53,800,000	109,800,000
Other segment costs (income)	800,000	1,800,000	2,600,000	5,300,000
Net income (loss) including noncontrolling interest	28,900,000	138,800,000	223,300,000	459,000,000.0
Additions to property, plant, equipment	111,600,000	130,200,000	586,400,000	511,300,000
Total assets at quarter-end	6,848,100,000	7,088,300,000	6,848,100,000	7,088,300,000
Operating Segments | Canada
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	500,000	300,000	1,300,000	1,200,000
Revenues from external customers	108,000,000.0	157,900,000	402,000,000.0	413,800,000
Lease operating expenses
Lease operating expenses and taxes other than income	41,200,000	51,700,000	133,100,000	142,100,000
Repair and maintenance	1,400,000	1,800,000	4,000,000.0	3,200,000
Workovers	100,000	300,000	900,000	2,800,000
Total lease operating expenses	42,700,000	53,800,000	138,000,000.0	148,100,000
Severance and ad valorem taxes	400,000	300,000	1,100,000	1,100,000
Transportation, gathering and processing	24,800,000	21,200,000	68,700,000	60,400,000
Costs of purchased natural gas				3,100,000
Selling and general expenses	5,400,000	4,700,000	17,100,000	14,200,000
Exploration Expenses
Geological and geophysical	100,000	100,000	100,000	200,000
Dry holes and previously suspended exploration costs	0	0	0	0
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	100,000	200,000	200,000	200,000
Total exploration expenses	200,000	300,000	300,000	400,000
Depreciation, depletion and amortization	39,300,000	42,800,000	109,800,000	114,100,000
Impairment of assets		0	0	0
Accretion of asset retirement obligations	2,600,000	2,100,000	7,700,000	6,400,000
Other operating expenses	100,000	100,000	1,800,000	2,100,000
Interest Income	0	0	0	0
Interest expense, net of capitalization	100,000	0	100,000	200,000
Income tax expense
Current income tax expense (benefit)	(1,700,000)	8,200,000	12,300,000	10,500,000
Deferred income tax expense (benefit)	(200,000)	200,000	(1,800,000)	700,000
Total income tax expense (benefit)	(1,900,000)	8,400,000	10,500,000	11,200,000
Other segment costs (income)	400,000	0	1,100,000	0
Net income (loss) including noncontrolling interest	(6,100,000)	24,200,000	45,800,000	52,500,000
Additions to property, plant, equipment	26,000,000.0	13,500,000	127,000,000.0	122,900,000
Total assets at quarter-end	1,981,800,000	2,043,000,000	1,981,800,000	2,043,000,000
Operating Segments | Other
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	0	0	0	0
Revenues from external customers	100,000	(800,000)	3,000,000.0	3,400,000
Lease operating expenses
Lease operating expenses and taxes other than income	400,000	300,000	1,600,000	1,000,000.0
Repair and maintenance	0	0	0	0
Workovers	0	0	0	0
Total lease operating expenses	400,000	300,000	1,600,000	1,000,000.0
Severance and ad valorem taxes	0	0	0	0
Transportation, gathering and processing	0	0	0	0
Costs of purchased natural gas				0
Selling and general expenses	2,200,000	1,900,000	6,700,000	4,900,000
Exploration Expenses
Geological and geophysical	1,100,000	2,800,000	1,600,000	8,600,000
Dry holes and previously suspended exploration costs	900,000	400,000	1,000,000.0	1,700,000
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	7,800,000	4,700,000	22,600,000	16,700,000
Total exploration expenses	9,800,000	7,900,000	25,200,000	27,000,000.0
Depreciation, depletion and amortization	0	0	1,200,000	900,000
Impairment of assets		0	0	0
Accretion of asset retirement obligations	200,000	200,000	600,000	600,000
Other operating expenses	200,000	500,000	(1,100,000)	600,000
Interest Income	0	0	0	0
Interest expense, net of capitalization	0	0	100,000	100,000
Income tax expense
Current income tax expense (benefit)	0	(100,000)	200,000	200,000
Deferred income tax expense (benefit)	(400,000)	(34,000,000.0)	(1,100,000)	(33,700,000)
Total income tax expense (benefit)	(400,000)	(34,100,000)	(900,000)	(33,500,000)
Other segment costs (income)	(300,000)	100,000	0	300,000
Net income (loss) including noncontrolling interest	(12,000,000.0)	22,400,000	(30,400,000)	1,500,000
Additions to property, plant, equipment	41,100,000	20,500,000	94,400,000	44,600,000
Total assets at quarter-end	411,800,000	266,600,000	411,800,000	266,600,000
Operating Segments | Revenue from production
Segment Reporting Information [Line Items]
Revenue from production	721,000,000.0	753,100,000	2,076,800,000	2,345,300,000
Operating Segments | Revenue from production | United States
Segment Reporting Information [Line Items]
Revenue from production	613,400,000	596,500,000	1,673,100,000	1,933,000,000
Operating Segments | Revenue from production | Canada
Segment Reporting Information [Line Items]
Revenue from production	107,500,000	157,600,000	400,700,000	408,900,000
Operating Segments | Revenue from production | Other
Segment Reporting Information [Line Items]
Revenue from production	100,000	(800,000)	3,000,000.0	3,400,000
Operating Segments | Sales of purchased natural gas
Segment Reporting Information [Line Items]
Revenue from production				3,700,000
Operating Segments | Sales of purchased natural gas | United States
Segment Reporting Information [Line Items]
Revenue from production				0
Operating Segments | Sales of purchased natural gas | Canada
Segment Reporting Information [Line Items]
Revenue from production				3,700,000
Operating Segments | Sales of purchased natural gas | Other
Segment Reporting Information [Line Items]
Revenue from production				0
Corporate, Other, and Discontinued Operations
Segment Reporting Information [Line Items]
Gain on sales of assets and other operating income	11,400,000	4,200,000	15,000,000.0	4,200,000
Revenues from external customers	11,400,000	4,200,000	15,000,000.0	4,200,000
Lease operating expenses
Lease operating expenses and taxes other than income	0	0	0	0
Repair and maintenance	0	0	0	0
Workovers	0	0	0	0
Total lease operating expenses	0	0	0	0
Severance and ad valorem taxes	0	0	0	0
Transportation, gathering and processing	0	0	0	0
Costs of purchased natural gas				0
Selling and general expenses	21,400,000	20,000,000.0	66,200,000	65,000,000.0
Exploration Expenses
Geological and geophysical	0	0	0	0
Dry holes and previously suspended exploration costs	0	0	0	0
Other exploratory costs, including undeveloped lease amortization and delay lease rentals	0	0	0	0
Total exploration expenses	0	0	0	0
Depreciation, depletion and amortization	2,100,000	1,500,000	6,200,000	7,000,000.0
Impairment of assets		0	0	0
Accretion of asset retirement obligations	100,000	0	100,000	100,000
Other operating expenses	(100,000)	100,000	3,000,000.0	(200,000)
Interest Income	(2,700,000)	(3,100,000)	(8,700,000)	(8,600,000)
Interest expense, net of capitalization	24,600,000	21,000,000.0	73,100,000	61,700,000
Income tax expense
Current income tax expense (benefit)	2,800,000	2,100,000	(100,000)	6,200,000
Deferred income tax expense (benefit)	(5,200,000)	(9,500,000)	(25,400,000)	(28,800,000)
Total income tax expense (benefit)	(2,400,000)	(7,400,000)	(25,500,000)	(22,600,000)
Other segment costs (income)	(12,500,000)	6,400,000	23,100,000	(7,200,000)
Net income (loss) including noncontrolling interest	(19,100,000)	(34,300,000)	(122,500,000)	(91,000,000.0)
Additions to property, plant, equipment	2,300,000	8,000,000.0	9,200,000	16,400,000
Total assets at quarter-end	491,100,000	318,500,000	491,100,000	318,500,000
Corporate, Other, and Discontinued Operations | Revenue from production
Segment Reporting Information [Line Items]
Revenue from production	$ 0	$ 0	$ 0	0
Corporate, Other, and Discontinued Operations | Sales of purchased natural gas
Segment Reporting Information [Line Items]
Revenue from production				$ 0