XML 61 R42.htm IDEA: XBRL DOCUMENT v3.20.4
Nature of Operations and Summary of Significant Accounting Policies - Long-Lived Assets (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Impairment of Long Lived and Intangible Assets      
Property and equipment and related assets $ 5,362,048 $ 5,394,681  
Impairment of long-lived assets $ 0 $ 0 $ 0