Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Write off of Deferred Debt Issuance Cost	$ 1,183	$ 2,764
Withholding taxes paid for conversion of employee stock awards	1,197	1,115
OPERATING ACTIVITIES:
Net earnings from continuing operations	42,290	133,733
Net earnings from discontinued operations	0	3,772
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	79,719	77,001
Pension and post-retirement	1,811	972
Deferred income taxes	12,575	7,947
Amortization of stock-based compensation	1,750	1,821
Net gain on financial instruments	(2,500)	10,900
Changes in assets and liabilities:
Accounts receivable	(1,604)	(4,123)
Inventory and prepaid supplies	751	(4,543)
Accounts payable	18,314	6,169
Unearned revenue	(3,687)	3,604
Accrued expenses, salaries, wages, benefits and other liabilities	(11,696)	(17,742)
Pension and post-retirement balances	(7,412)	(5,483)
Other	(75)	186
NET CASH PROVIDED BY OPERATING ACTIVITIES	124,447	99,034
INVESTING ACTIVITIES:
Expenditures for property and equipment	(125,441)	(143,495)
Proceeds from property and equipment	44	32
Investment in nonconsolidated affiliate	(1,697)	(3,049)
NET CASH USED IN INVESTING ACTIVITIES	(127,094)	(146,512)
FINANCING ACTIVITIES:
Principal payments on long term obligations	(124,065)	(499,064)
Proceeds from borrowings	140,000	80,000
Payments for financing costs	(151)	(7,481)
Proceeds from Issuance of Unsecured Debt	0	500,000
NET CASH PROVIDED BY FINANCING ACTIVITIES	14,587	72,340
NET INCREASE IN CASH AND CASH EQUIVALENTS	11,940	24,862
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	39,719	46,201
CASH AND CASH EQUIVALENTS AT END OF PERIOD	51,659	71,063
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid, net of amount capitalized	16,582	8,864
Federal and state income taxes paid	123	48
SUPPLEMENTAL NON-CASH INFORMATION:
Accrued expenditures for property and equipment	24,253	27,914
Net (gain) loss on financial instruments	$ 9,472	$ 107,044