| Pay vs Performance Disclosure | 12 Months Ended |
| Dec. 31, 2022 USD ($) $ / shares | Dec. 31, 2021 USD ($) $ / shares | Dec. 31, 2020 USD ($) $ / shares | Dec. 31, 2019 USD ($) |
| Pay vs Performance Disclosure [Table] | | | | |
| Pay vs Performance [Table Text Block] | Year 1 Summary Compensation Table Total Compensation for Principal Executive Officer (PEO) 2 ($) Compensation Actually Paid to PEO 3 ($) Average Summary Compensation Table Total Compensation for Non-PEO Named Executive Officers 4 ($) Average Compensation Actually Paid to Non-PEO Named Executive Officers 5 ($) Value of initial fixed $100 investment based on: Net Income 8 (in thousands) ($) Company Selected Measure - Earnings per Share 9 ($) Total Stockholder Return 6 ($) Peer Group Total Stockholder Return 7 ($) 2022 5,257,289 5,644,274 1,901,639 1,998,863 111.98 123.90 367,489 1.81 2021 5,210,467 7,143,972 1,810,584 2,273,834 110.37 128.00 378,131 1.87 2020 6,423,410 5,664,783 2,042,921 1,901,274 91.69 101.04 390,205 1.95 | | | |
| Named Executive Officers, Footnote [Text Block] | Our PEO for years 2020, 2021 and 2022 was David L. Goodin. Our non-PEO named executive officers (NEO) for 2020, 2021 and 2022 were Jason L. Vollmer, David C. Barney, Jeffrey S. Thiede and Nicole A. Kivisto. | | | |
| Peer Group Issuers, Footnote [Text Block] | Represents the value of $100 invested in the compensation peer group company stock on December 31, 2019 as of December 31.2020, December 31, 2021 and December 31, 2022 assuming dividends are reinvested in the compensation peer group stock at the frequency paid. Returns of each peer group company are weighted according to the peer group company’s market capitalization at the beginning of the period. Our compensation benchmarking peer group companies for 2020, 2021 and 2022 included: 2020 2021 2022 Alliant Energy Alliant Energy Alliant Energy Ameren Corporation Ameren Corporation Ameren Corporation Atmos Energy Corporation Atmos Energy Corporation Atmos Energy Corporation Black Hills Corporation Black Hills Corporation Black Hills Corporation CMS Energy Corporation CMS Energy Corporation CMS Energy Corporation Dycom Industries, Inc. Dycom Industries, Inc. Dycom Industries, Inc. EMCOR Group, Inc. EMCOR Group, Inc. EMCOR Group, Inc. Evergy, Inc. Evergy, Inc. Evergy, Inc. Granite Construction Incorporated Granite Construction Incorporated Granite Construction Incorporated Jacobs Engineering Group Inc. Jacobs Engineering Group Inc.* KRB, Inc. KRB, Inc. KRB, Inc. Martin Marietta Materials, Inc. Martin Marietta Materials, Inc. Martin Marietta Materials, Inc. MasTec, Inc. MasTec, Inc. MasTec, Inc. MYR Group, Inc.* NiSource Inc. NiSource Inc. NiSource Inc. Pinnacle West Capital Corporation Pinnacle West Capital Corporation Pinnacle West Capital Corporation Portland General Electric Company Portland General Electric Company Portland General Electric Company Quanta Services, Inc. Quanta Services, Inc. Quanta Services, Inc. Southwest Gas Holdings, Inc. Southwest Gas Holdings, Inc. Southwest Gas Holdings, Inc. Summit Materials, Inc. Summit Materials, Inc. Summit Materials, Inc. Vulcan Materials Company Vulcan Materials Company Vulcan Materials Company WEC Energy Group, Inc. WEC Energy Group, Inc. WEC Energy Group, Inc. * Jacobs Engineering Group, Inc. was replaced with MYR Group Inc. in 2022 due to size. Total stockholder return for the peer group companies for 12/31/2020, 12/31/2021 and 12/31/2022 were as follows 12/31/2019 12/31/2020 12/31/2021 12/31/2022 Peer group with Jacobs Engineering Group Inc. $ 100.00 $ 101.04 $ 128.00 $ 124.22 Peer group with MYR Group, Inc. $ 100.00 $ 100.01 $ 126.85 $ 123.90 | | | |
| PEO Total Compensation Amount | $ 5,257,289 | $ 5,210,467 | $ 6,423,410 | |
| PEO Actually Paid Compensation Amount | 5,644,274 | 7,143,972 | 5,664,783 | |
| Non-PEO NEO Average Total Compensation Amount | 1,901,639 | 1,810,584 | 2,042,921 | |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,998,863 | 2,273,834 | 1,901,274 | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | CAP vs. TSR Our TSR is a reflection of our stock price and dividends paid over a period of time and is important to stockholders as it measures the performance of an investment in our company stock in the marketplace. The following charts depicts the PEO and average non-PEO named executive officer CAP compared to the value of $100 invested in company and peer company stock on December 31, 2019 as of December 31, 2020, December 31, 2021 and December 31, 2022 assuming dividends are reinvested in company stock at the frequency paid. | | | |
| Compensation Actually Paid vs. Net Income [Text Block] | CAP vs. Net Income The following charts depicts the PEO and average non-PEO NEO CAP compared to the company’s net income for 2020, 2021 and 2022. CAP vs. EPS The following charts depicts the PEO and average non-PEO named executive officer CAP compared to the company’s EPS for 2020, 2021 and 2022. | | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | | | | |
| Total Shareholder Return Amount | $ 111.98 | 110.37 | 91.69 | |
| Net Income (Loss) | $ 367,489,000 | $ 378,131,000 | $ 390,205,000 | |
| Company Selected Measure Amount | $ / shares | 1.81 | 1.87 | 1.95 | |
| PEO Name | David L. Goodin | | | |
| Measure [Axis]: 1 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | Earnings per Share | | | |
| Measure [Axis]: 2 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | Earnings Growth from Continuing Operations | | | |
| Measure [Axis]: 3 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | Relative Total Stockholder Return | | | |
| MYR Group, Inc. [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Peer Group Total Shareholder Return Amount | $ 123.90 | $ 126.85 | $ 100.01 | $ 100 |
| Jacobs Engineering Group Inc. [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Peer Group Total Shareholder Return Amount | 124.22 | 128 | 101.04 | $ 100 |
| PEO [Member] | Equity Award Values Reported in the SCT [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 3,247,775 | 3,222,639 | 2,974,497 | |
| PEO [Member] | Equity Award Adjustments [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 3,634,760 | 5,156,144 | 2,651,451 | |
| PEO [Member] | Changes to Pension Reported in SCT [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 435,581 | |
| PEO [Member] | Aggregated Service Cost and Prior Service Cost [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| PEO [Member] | YE Value of Equity Awards Granted during year which are Unvested [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 3,665,234 | 3,586,652 | 2,402,446 | |
| PEO [Member] | Y o Y Change in Value of Equity Awards Granted in Prior Years which are Unvested [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (198,017) | (90,005) | (557,760) | |
| PEO [Member] | Value at Vesting Date of Equity Awards Granted and Vesting in the Year [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| PEO [Member] | Y o Y Change in Value of Equity Awards Granted in prior years which Vest in Year [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 167,543 | 1,659,497 | 806,765 | |
| PEO [Member] | PYE Value of Equity Awards that Failed to Meet Vesting Conditions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | | 0 | |
| PEO [Member] | Value of Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Value or Total Compensation [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| Non-PEO NEO [Member] | Equity Award Values Reported in the SCT [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 862,681 | 870,757 | 707,370 | |
| Non-PEO NEO [Member] | Equity Award Adjustments [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 959,905 | 1,334,007 | 634,637 | |
| Non-PEO NEO [Member] | Changes to Pension Reported in SCT [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 68,914 | |
| Non-PEO NEO [Member] | Aggregated Service Cost and Prior Service Cost [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| Non-PEO NEO [Member] | YE Value of Equity Awards Granted during year which are Unvested [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 973,569 | 969,113 | 571,330 | |
| Non-PEO NEO [Member] | Y o Y Change in Value of Equity Awards Granted in Prior Years which are Unvested [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (53,505) | (21,403) | (129,852) | |
| Non-PEO NEO [Member] | Value at Vesting Date of Equity Awards Granted and Vesting in the Year [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| Non-PEO NEO [Member] | Y o Y Change in Value of Equity Awards Granted in prior years which Vest in Year [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 39,841 | 386,297 | 193,159 | |
| Non-PEO NEO [Member] | PYE Value of Equity Awards that Failed to Meet Vesting Conditions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 | |
| Non-PEO NEO [Member] | Value of Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Value or Total Compensation [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 0 | |
