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Summary of significant accounting policies (Tables) | 12 Months Ended
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Dec. 31, 2015
Accounting Policies [Abstract] |
Inventories | Inventories at December 31 consisted of:
| 2015 |  | 2014 |
| (In thousands)
Aggregates held for resale | $ | 115,854 |  | $ | 108,161 |
Asphalt oil | 36,498 |  | 42,135 |
Materials and supplies | 16,997 |  | 54,282 |
Merchandise for resale | 15,318 |  | 24,420 |
Refined products | 8,498 |  | — |
Natural gas in storage (current) | 21,023 |  | 19,302 |
Crude oil | 4,678 |  | 5,045 |
Other | 34,861 |  | 36,065 |
Total | $ | 253,727 |  | $ | 289,410 |
AFUDC and interest capitailized | The amount of AFUDC and interest capitalized for the years ended December 31 were as follows:
| 2015 |  | 2014 |  | 2013 |
|  | (In thousands) |  |
Interest capitalized | $ | 4,902 |  | $ | 8,586 |  | $ | 6,033 |
AFUDC - borrowed | $ | 4,907 |  | $ | 3,022 |  | $ | 2,767 |
AFUDC - equity | $ | 7,971 |  | $ | 5,803 |  | $ | 3,322 |
Property, plant and equipment | Property, plant and equipment at December 31 was as follows:
| 2015 |  | 2014 |  | Weighted Average Depreciable Life in Years
| (Dollars in thousands, where applicable)
Regulated: |  |  |
Electric: |  |  |
Generation | $ | 1,003,173 |  | $ | 627,952 |  | 39
Distribution | 375,612 |  | 343,692 |  | 44
Transmission | 255,842 |  | 229,997 |  | 57
Construction in progress | 42,436 |  | 150,445 |  | -
Other | 109,085 |  | 105,015 |  | 14
Natural gas distribution: |  |  |  |  |
Distribution | 1,624,645 |  | 1,481,390 |  | 35
Construction in progress | 20,530 |  | 59,310 |  | -
Other | 431,406 |  | 364,059 |  | 22
Pipeline and midstream: |  |  |  |  |
Transmission | 460,305 |  | 449,276 |  | 53
Gathering | 37,831 |  | 39,595 |  | 20
Storage | 44,011 |  | 43,994 |  | 60
Construction in progress | 7,549 |  | 5,386 |  | -
Other | 40,168 |  | 39,910 |  | 33
Nonregulated: |  |  |  |  |
Pipeline and midstream: |  |  |  |  |
Gathering and processing | 158,949 |  | 227,598 |  | 16
Construction in progress | 89 |  | 691 |  | -
Other | 9,827 |  | 11,938 |  | 10
Construction materials and contracting: |  |  |  |  |
Land | 123,723 |  | 125,372 |  | -
Buildings and improvements | 69,011 |  | 70,566 |  | 19
Machinery, vehicles and equipment | 937,084 |  | 921,564 |  | 12
Construction in progress | 18,615 |  | 8,709 |  | -
Aggregate reserves | 404,995 |  | 403,731 |  | *
Construction services: |  |  |  |  |
Land | 6,460 |  | 5,265 |  | -
Buildings and improvements | 23,824 |  | 17,936 |  | 25
Machinery, vehicles and equipment | 121,940 |  | 112,973 |  | 6
Other | 11,055 |  | 8,221 |  | 3
Refining: |  |  |
Refinery | 445,198 |  | 88,232 |  | 20
Construction in progress | 135 |  | 313,613 |  | -
Other: |  |  |  |  |
Land | 2,837 |  | 2,837 |  | -
Other | 46,700 |  | 48,100 |  | 23
Eliminations | (15,367 | ) | (12,589 | ) |
Less accumulated depreciation, depletion and amortization | 2,506,571 |  | 2,386,113 |  |
Net property, plant and equipment | $ | 4,311,097 |  | $ | 3,908,665 |  |
* | Depleted on the units-of-production method.
Percentage-of-completion method | Costs and estimated earnings in excess of billings and billings in excess of costs and estimated earnings on uncompleted contracts at December 31 were as follows:
| 2015 |  | 2014 |
| (In thousands)
Costs and estimated earnings in excess of billings on uncompleted contracts | $ | 64,369 |  | $ | 58,243 |
Billings in excess of costs and estimated earnings on uncompleted contracts | $ | 68,048 |  | $ | 47,011 |
Amounts representing balances billed but not paid by customers under retainage provisions in contracts at December 31 were as follows:
| 2015 |  | 2014 |
| (In thousands)
Short-term retainage* | $ | 46,207 |  | $ | 47,551 |
Long-term retainage** | 1,605 |  | 1,053 |
Total retainage | $ | 47,812 |  | $ | 48,604 |
* | Expected to be paid within one year or less and included in receivables, net.
** | Included in deferred charges and other assets - other.
Schedule of earnings per share reconciliation | Net income (loss) was the same for both the basic and diluted earnings (loss) per share calculations. A reconciliation of the weighted average common shares outstanding used in the basic and diluted earnings (loss) per share calculation was as follows:
| 2015 |  | 2014 |  | 2013 |
|  | (In thousands) |  |
Weighted average common shares outstanding - basic | 194,928 |  | 192,507 |  | 188,855 |
Effect of dilutive performance share awards | 58 |  | 80 |  | 838 |
Weighted average common shares outstanding - diluted | 194,986 |  | 192,587 |  | 189,693 |
Shares excluded from the calculation of diluted earnings per share | — |  | — |  | — |
Cash expenditures for interest and income taxes and noncash investing transactions | Cash expenditures for interest and income taxes for the years ended December 31 were as follows:
| 2015 |  | 2014 |  | 2013 |
|  | (In thousands) |  |
Interest, net of amount capitalized and AFUDC - borrowed of $9,809, $11,608 and $8,800 in 2015, 2014 and 2013, respectively | $ | 90,386 |  | $ | 81,241 |  | $ | 81,575 |
Income taxes paid, net | $ | 33,409 |  | $ | 64,211 |  | $ | 52,580 |
Noncash investing transactions at December 31 were as follows:
| 2015 |  | 2014 |  | 2013 |
|  | (In thousands) |  |
Property, plant and equipment additions in accounts payable | $ | 51,702 |  | $ | 62,453 |  | $ | 22,832 |
After-tax changes in the components of accumulated other comprehensive income (loss) | The after-tax changes in the components of accumulated other comprehensive loss as of December 31, 2015, 2014 and 2013, were as follows:
| Net Unrealized Gain (Loss) on Derivative Instruments Qualifying as Hedges |  | Post- retirement Liability Adjustment |  | Foreign Currency Translation Adjustment |  | Net Unrealized Gain (Loss) on Available- for-sale Investments |  | Total Accumulated Other Comprehensive Loss |
|  |  | (In thousands) |  |  |
Balance at December 31, 2013 | $ | (3,765 | ) | $ | (33,807 | ) | $ | (667 | ) | $ | 34 |  | $ | (38,205 | )
Other comprehensive income (loss) before reclassifications | — |  | (12,409 | ) | (162 | ) | (154 | ) | (12,725 | )
Amounts reclassified from accumulated other comprehensive loss | 694 |  | 796 |  | — |  | 135 |  | 1,625 |
Amounts reclassified from accumulated other comprehensive loss to a regulatory asset | — |  | 7,202 |  | — |  | — |  | 7,202 |
Net current-period other comprehensive income (loss) | 694 |  | (4,411 | ) | (162 | ) | (19 | ) | (3,898 | )
Balance at December 31, 2014 | (3,071 | ) | (38,218 | ) | (829 | ) | 15 |  | (42,103 | )
Other comprehensive income (loss) before reclassifications | — |  | (88 | ) | (173 | ) | (170 | ) | (431 | )
Amounts reclassified from accumulated other comprehensive loss | 404 |  | 1,794 |  | 802 |  | 131 |  | 3,131 |
Amounts reclassified from accumulated other comprehensive loss to a regulatory asset | — |  | 2,255 |  | — |  | — |  | 2,255 |
Net current-period other comprehensive income (loss) | 404 |  | 3,961 |  | 629 |  | (39 | ) | 4,955 |
Balance at December 31, 2015 | $ | (2,667 | ) | $ | (34,257 | ) | $ | (200 | ) | $ | (24 | ) | $ | (37,148 | )
Reclassification out of accumulated other comprehensive income (loss) | Reclassifications out of accumulated other comprehensive loss for the years ended December 31 were as follows:
| 2015 |  | 2014 |  | Location on Consolidated Statements of Income
| (In thousands) |
Reclassification adjustment for loss on derivative instruments included in net income (loss): |  |  |
Interest rate derivative instruments | $ | (637 | ) | $ | (639 | ) | Interest expense
| 233 |  | 240 |  | Income taxes
| (404 | ) | (399 | ) |
Commodity derivative instruments, net of tax | — |  | (295 | ) | Income (loss) from discontinued operations, net of tax
| (404 | ) | (694 | ) |
Amortization of postretirement liability losses included in net periodic benefit cost (credit) | (2,922 | ) | (1,288 | ) | (a)
| 1,128 |  | 492 |  | Income taxes
| (1,794 | ) | (796 | ) |
Reclassification adjustment for loss on foreign currency translation adjustment included in net income (loss) | (1,292 | ) | — |  | Other income
| 490 |  | — |  | Income taxes
| (802 | ) | — |  |
Reclassification adjustment for loss on available-for-sale investments included in net income (loss) | (201 | ) | (208 | ) | Other income
| 70 |  | 73 |  | Income taxes
| (131 | ) | (135 | ) |
Total reclassifications | $ | (3,131 | ) | $ | (1,625 | ) |
(a) | Included in net periodic benefit cost (credit). For more information, see Note 14.

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