Consolidated Balance Sheets Parentheticals - USD ($) shares in Thousands	Sep. 30, 2021	Dec. 31, 2020
Consolidated Balance Sheets [Abstract]
Accumulated depreciation and amortization, property and equipment	$ 4,849,000	$ 5,815,000
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	225,000	225,000
Common stock, shares issued	149,987	142,289
Treasury stock, shares	1,165	793