Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts receivable, credit loss reserve	$ 8,488	$ 7,931
Accumulated depreciation	$ 1,685,556	$ 1,657,709
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	121,586,000	120,285,000
Common stock, shares outstanding	121,586,000	120,285,000