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Financing: At-the-Market Equity Offering Program (Details) - Common Stock - USD ($) | 3 Months Ended | 9 Months Ended
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Proceeds, (net of issuance costs) | $ 154,300,000 | $ 108,600,000 | $ 219,600,000 | $ 181,600,000
Average price per share | $ 59.47 | $ 56.84 | $ 59.56 | $ 55.63
Number of shares issued | 2,600,000 | 1,900,000 | 3,700,000 | 3,300,000
Payments of Stock Issuance Costs | $ (1,300,000) | $ (1,100,000) | $ (2,000,000) | $ (1,800,000)
June 16, 2023 ATM Program |  |  |  |
Proceeds, (net of issuance costs) | $ 0 | $ 108,600,000 | $ 45,700,000 | $ 181,600,000
Number of shares issued | 0 | 1,900,000 | 800,000 | 3,300,000
Payments of Stock Issuance Costs | $ 0 | $ (1,100,000) | $ (500,000) | $ (1,800,000)
May 8, 2025 ATM Program |  |  |  |
Proceeds, (net of issuance costs) | $ 154,300,000 | $ 0 | $ 173,900,000 | $ 0
Number of shares issued | 2,600,000 | 0 | 2,900,000 | 0
Payments of Stock Issuance Costs | $ (1,300,000) | $ 0 | $ (1,500,000) | $ 0

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- Definition At the market equity offering program average price per share. + References No definition available. + Details
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- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-15 + Details
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