Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation - Other than Options (Details)

v3.20.4
Stock-based Compensation - Other than Options (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Restricted Stock and Restricted Stock Units | Common Stock Class A and C      
Stock Based Compensation      
Fair value of outstanding grants $ 5,400 $ 2,600 $ 112
Restricted Stock and Restricted Stock Units | Series A Cumulative Redeemable Preferred Stock      
Stock Based Compensation      
Vested shares 0    
Restricted Stock and Restricted Stock Units | Common Stok Class A and C, Series A cumulative redeemable preferred stock      
Stock Based Compensation      
Unvested shares outstanding 406,000    
Weighted average grant date fair value awards outstanding unvested (in dollars per share) $ 136.86    
Skyhook | LTIPs | PARs and PSUs | Other liabilities | Significant other observable inputs (Level 2)      
Stock Based Compensation      
Deferred compensation $ 700 $ 1,200