CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ 37,302	$ (19,931)	$ (50,571)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	324,864	381,237	432,668
Deferred income taxes	8,386	(5,249)	(26,008)
Cash distributions from wireless partnerships in excess of (less than) current earnings	844	(1,901)	(194)
Pension and post-retirement contributions in excess of expense	(37,301)	(24,507)	(30,361)
Stock-based compensation expense	7,533	6,836	5,119
Amortization of deferred financing costs and discounts	7,871	4,932	4,721
Loss (gain) on extinguishment of debt	10,629	(4,510)
Gain on change in fair value of contingent payment rights	(23,802)
Other, net	5,374	1,487	6,066
Changes in operating assets and liabilities:
Accounts receivable, net	(4,993)	13,120	(2,044)
Income tax receivable	3,103	9,908	10,754
Prepaid expenses and other assets	(7,457)	(1,546)	(12,785)
Accounts payable	(5,653)	(1,566)	8,359
Accrued expenses and other liabilities	38,280	(19,214)	11,597
Net cash provided by operating activities	364,980	339,096	357,321
Cash flows from investing activities:
Purchases of property, plant and equipment, net	(217,563)	(232,203)	(244,816)
Proceeds from sale of assets	7,071	14,718	2,125
Proceeds from business dispositions			20,999
Proceeds from sale of investments	426	329	233
Other		(663)
Net cash used in investing activities	(210,066)	(217,819)	(221,459)
Cash flows from financing activities:
Proceeds from bond offering	750,000
Proceeds from issuance of long-term debt	1,271,250	195,000	189,588
Proceeds from issuance of common stock	350,000
Payment of finance lease obligations	(9,020)	(12,519)	(12,755)
Payment on long-term debt	(1,867,838)	(195,350)	(207,938)
Retirement of senior notes	(444,717)	(49,804)
Payment of financing costs	(59,139)
Share repurchases for minimum tax withholding	(812)	(363)	(593)
Dividends on common stock		(55,445)	(110,222)
Other	(1,472)
Net cash used in financing activities	(11,748)	(118,481)	(141,920)
Change in cash and cash equivalents	143,166	2,796	(6,058)
Cash and cash equivalents at beginning of period	12,395	9,599	15,657
Cash and cash equivalents at end of period	$ 155,561	$ 12,395	$ 9,599