CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Cash flows from operating activities:
Net income	$ (708)	$ 1,967	$ 34,872
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation and amortization	88,311	89,125	85,719
Provision for doubtful accounts	5,010	5,816	5,134
Amortization of debt discount and debt issuance costs	530	542	763
Stock-based compensation	5,912	6,384	6,420
Deferred income taxes	(7,317)	(2,192)	(23,242)
Loss on equity investments	3,427	4,724
(Gain) loss on disposition of long-lived assets	21,572	2,841	(26,425)
Goodwill impairment	0	3,279	0
Unrealized loss on foreign currency	357	362	1,342
Other non-cash activity		(42)	308
Changes in operating assets and liabilities, excluding the effects of acquisitions and dispositions:
Accounts receivable	(17,774)	(3,511)	(1,682)
Materials and supplies, prepayments, and other current assets	(18,624)	(1,613)	5,924
Prepaid income taxes	2,218	4,581	3,147
Accounts payable and accrued liabilities, advance payments and deposits and other current liabilities	12,597	(2,536)	(7,044)
Accrued taxes	799	(19,053)	29,089
Other assets	(8,790)	(5,711)	(238)
Other liabilities	(1,236)	2,940	1,778
Net cash provided by operating activities	86,284	87,903	115,865
Cash flows from investing activities:
Capital expenditures	(75,323)	(72,602)	(105,769)
Hurricane rebuild capital expenditures		(123)	(80,152)
Hurricane insurance proceeds			34,606
Receipt of government grants	16,316	3,140	5,400
Divestiture of businesses, net of transferred cash of $0.0 million, $0.0 million, and $11.5 million, respectively		6,572	48,270
Purchase of spectrum; including deposits	(20,396)
Purchases of strategic investments	(2,768)	(25,362)	(3,000)
Proceeds from strategic investments	11,969
Purchase of short-term investments	(116)	(8,028)	(138)
Proceeds from disposition of long-lived assets			6,900
Proceeds from sale of short-term investments	120	8,141	6,564
Net cash used in investing activities	(70,198)	(88,262)	(87,319)
Cash flows from financing activities:
Dividends paid on common stock	(10,891)	(10,880)	(10,866)
Distributions to non-controlling interests	(10,368)	(7,161)	(18,780)
Payment of debt issuance costs	(1,096)	(1,340)
Principal repayments of term loan	(13,751)	(4,700)	(9,795)
Proceeds from stock option exercises			72
Purchases of common stock - stock-based compensation	(1,733)	(1,649)	(4,622)
Purchases of common stock - share repurchase plan	(6,589)	(162)	(1,576)
Repurchases of non-controlling interests	(28,939)	(4,504)	(9,663)
Investments made by minority shareholders in consolidated affiliates		488
Net cash used in financing activities	(73,367)	(29,908)	(55,230)
Effect of foreign currency exchange rates on cash and cash equivalents	(80)	(282)	(299)
Net change in cash, cash equivalents, and restricted cash	(57,361)	(30,549)	(26,983)
Total cash, cash equivalents, and restricted cash, beginning of period	162,358	192,907	219,890
Total cash, cash equivalents, and restricted cash, end of period	104,997	162,358	192,907
Supplemental cash flow information:
Interest paid	4,829	4,554	7,235
Taxes paid	6,117	30,411	12,486
Dividends declared, not paid	2,703	2,721	2,720
Noncash investing activity:
Transfer (to) from operating activities to property, plant and equipment	(1,219)		6,708
Purchases of property, plant and equipment included in accounts payable and accrued expenses	$ 21,746	$ 11,668	$ 12,877