Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities:
Net income	$ 841,100,000	$ 461,000,000.0	$ 696,400,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization of intangibles	417,500,000	409,900,000	387,500,000
Amortization of deferred financing costs	4,400,000	2,600,000	23,400,000
Loss on early extinguishment of debt	56,100,000	0	22,200,000
Share-based compensation expense	35,500,000	30,000,000.0	30,400,000
Deferred income tax provision	59,400,000	34,700,000	60,300,000
Goodwill impairment	0	55,200,000	0
Net loss on asset disposals	6,100,000	6,800,000	8,200,000
Pension and post-retirement benefits expense, net of contributions	(50,500,000)	(63,400,000)	(26,900,000)
Other, net	11,900,000	18,200,000	(3,400,000)
(Increase) decrease in assets -
Accounts receivable	(227,200,000)	13,200,000	56,400,000
Inventories	(105,500,000)	6,300,000	1,400,000
Prepaid expenses and other current assets	(2,700,000)	400,000	(6,900,000)
Increase (decrease) in liabilities —
Accounts payable	12,200,000	39,700,000	(32,400,000)
Accrued liabilities	37,900,000	(3,200,000)	(100,000)
Federal and state income tax payable / receivable	(2,100,000)	21,400,000	(9,100,000)
Net cash provided by operating activities	1,094,100,000	1,032,800,000	1,207,400,000
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	(605,100,000)	(421,200,000)	(399,500,000)
Acquisitions of businesses, net of cash acquired	(194,900,000)	0	0
Additions to other long-term assets	(1,800,000)	(6,400,000)	(3,800,000)
Proceeds from asset disposals	7,900,000	4,600,000	4,100,000
Purchases of marketable debt securities	(127,400,000)	(110,100,000)	(157,000,000.0)
Proceeds from sales of marketable debt securities	26,700,000	24,200,000	10,900,000
Proceeds from maturities of marketable debt securities	100,200,000	82,800,000	0
Other, net	0	0	(1,300,000)
Net cash used for investing activities	(794,400,000)	(426,100,000)	(546,600,000)
Cash Flows from Financing Activities:
Net proceeds received from issuance of debt	690,200,000	0	889,000,000.0
Repayments of debt and finance lease obligations	(757,700,000)	(1,500,000)	(923,400,000)
Financing costs paid	(2,400,000)	0	(1,500,000)
Common stock dividends paid	(379,800,000)	(299,600,000)	(298,700,000)
Repurchases of common stock	(193,000,000.0)	0	0
Shares withheld to cover employee restricted stock taxes	(12,900,000)	(10,500,000)	(8,200,000)
Net cash used for financing activities	(655,600,000)	(311,600,000)	(342,800,000)
Net increase in cash and cash equivalents	(355,900,000)	295,100,000	318,000,000.0
Cash and cash equivalents, beginning of year	974,600,000	679,500,000	361,500,000
Cash and cash equivalents, end of year	$ 618,700,000	$ 974,600,000	$ 679,500,000