Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 54,137	$ 9,777
Restricted cash and equivalents	4,027	3,881
Accounts receivable, net	238,903	255,805
Materials, supplies and fuel	92,894	117,172
Derivative assets, current	1,780	342
Income tax receivable, net	22,319	16,446
Regulatory assets, current	49,415	43,282
Other current assets	26,198	26,479
Total current assets	489,673	473,184
Investments	15,250	21,929
Property, plant and equipment	6,808,261	6,784,679
Less: accumulated depreciation and depletion	(1,223,979)	(1,281,493)
Total property, plant and equipment, net	5,584,282	5,503,186
Other assets:
Goodwill	1,299,454	1,299,454
Intangible assets, net	13,083	13,266
Regulatory assets, non-current	222,814	228,062
Other assets, non-current	24,258	19,376
Total other assets, non-current	1,559,609	1,560,158
TOTAL ASSETS	7,648,814	7,558,457
Current liabilities:
Accounts payable	136,344	193,523
Accrued liabilities	203,445	226,767
Derivative liabilities, current	852	2,254
Regulatory liabilities, current	54,345	33,507
Notes payable	319,125	349,500
Current maturities of long-term debt	5,743	5,743
Total current liabilities	719,854	811,294
Long-term debt, net of current maturities	3,136,887	3,140,096
Deferred credits and other liabilities:
Deferred Income Tax Liabilities, Net	387,939	360,719
Regulatory liabilities, non-current	504,149	503,145
Benefit plan liabilities	152,693	154,472
Other deferred credits and other liabilities	122,869	124,662
Total deferred credits and other liabilities	1,167,650	1,142,998
Commitments and contingencies (See Notes 7, 9, 12, 13)
Equity:
Common stock $1 par value; 100,000,000 shares authorized; issued 62,772,978 and 61,480,658 shares, respectively	62,773	61,481
Additional paid-in capital	1,652,861	1,552,788
Retained earnings	838,841	778,776
Treasury stock, at cost – 24,656 and 3,956 shares, respectively	(1,925)	(267)
Accumulated other comprehensive income (loss)	(29,382)	(30,655)
Total stockholders’ equity	2,523,168	2,362,123
Noncontrolling interest	101,255	101,946
Total equity	2,624,423	2,464,069
TOTAL LIABILITIES AND TOTAL EQUITY	$ 7,648,814	$ 7,558,457