Property, Plant, and Equipment

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment Disclosure

Property, Plant and Equipment

Property, plant and equipment at December 31 was as follows:

	2020		2019		Weighted Average Depreciable Life in Years
	(Dollars in thousands, where applicable)
Regulated:
Electric:
Generation	$	1,133,390	$	1,139,059	48
Distribution	464,442		443,780		46
Transmission	524,155		445,485		64
Construction in progress	61,766		66,664		—
Other	139,650		132,157		14
Natural gas distribution:
Distribution	2,302,121		2,133,249		47
Transmission	104,695		104,401		51
Storage	33,014		31,484		24
General	198,211		191,446		14
Construction in progress	16,836		39,506		—
Other	213,976		188,037		16
Pipeline:
Transmission	665,567		636,796		46
Gathering	—		35,661		—
Storage	52,632		50,001		53
Construction in progress	46,690		22,597		—
Other	49,640		48,340		17
Non-regulated:
Pipeline:
Gathering	—		31,148		—
Construction in progress	4		154		—
Other	7,164		9,518		11
Construction materials and contracting:
Land	132,948		127,729		—
Buildings and improvements	130,417		122,064		21
Machinery, vehicles and equipment	1,284,604		1,180,343		12
Construction in progress	23,803		25,018		—
Aggregate reserves	456,704		455,408		**
Construction services:
Land	7,218		7,146		—
Buildings and improvements	41,674		31,735		25
Machinery, vehicles and equipment	163,080		156,537		7
Other	8,824		17,952		4
Other:
Land	2,648		2,648		—
Other	34,897		32,565		12
Less accumulated depreciation, depletion and amortization	3,133,831		2,991,486
Net property, plant and equipment	$	5,166,939	$	4,917,142

*Depleted on the units-of-production method based on recoverable aggregate reserves.