CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Receivables, allowances	$ 684	$ 598
Less accumulated depreciation	791,835	732,279
Intangible assets, accumulated amortization	$ 366,001	$ 330,070
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	32,230,000	31,873,000
Common stock, shares outstanding (in shares)	32,230,000	31,873,000