XML 76 R63.htm IDEA: XBRL DOCUMENT v3.21.2
Organization and Basis of Presentation (Details)
 6 Months Ended 12 Months Ended
Jul. 02, 2021
USD ($)
shares
Jun. 28, 2021
USD ($)
shares
Jun. 25, 2021
USD ($)
shares
Nov. 30, 2020
USD ($)
shares
Dec. 02, 2019
USD ($)
shares
Sep. 26, 2018
USD ($)
tranche
shares
Jun. 28, 2013
USD ($)
shares
Jun. 30, 2021
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
Jul. 01, 2021
$ / shares
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Nov. 30, 2019
USD ($)
Jun. 18, 2018
USD ($)
Description Of Business                            
Shares settled (in shares) | shares       741,505 898,685     944,329            
Investment owned shares settled fair value       $ 93,500,000 $ 93,500,000     $ 166,000,000.0            
Shares owned (in shares) | shares       250,742 93,562     5,278,011            
Marketable securities               $ 1,093,887,000     $ 33,283,000      
Assets               4,634,095,000     3,982,450,000      
Total liabilities               3,042,468,000     3,041,258,000      
Retained earnings               $ 805,720,000     342,764,000      
2021 Equity Event                            
Description Of Business                            
Compensation expense   $ 428,600,000                        
Deferred tax asset, net of allowance   101,000,000.0                        
Settlement share price (usd per share) | $ / shares               $ 12.50            
Common Class A | 2021 Equity Event                            
Description Of Business                            
Limited partnership units conversion ratio   $ 0.9403                        
Subsequent Event | 2021 Equity Event                            
Description Of Business                            
Settlement share price (usd per share) | $ / shares                   $ 13.01        
Common Stock | Nasdaq                            
Description Of Business                            
Fair value of equity security     $ 1,093,900,000         $ 1,093,900,000     $ 33,300,000      
Cumulative Effect, Period of Adoption, Adjustment                            
Description Of Business                            
Assets                       $ (8,000,000.0)    
Total liabilities                       17,900,000    
Retained earnings                       $ (25,900,000)    
Nasdaq Earn-Out | Common Stock                            
Description Of Business                            
Shares settled (in shares) | shares     6,222,340                      
Fair value of equity security       $ 121,900,000                    
Marketable securities                         $ 98,600,000  
Nasdaq Earn-Out | Common Stock | Subsequent Event                            
Description Of Business                            
Shares settled (in shares) | shares 944,329                          
Fair value of equity security $ 166,000,000.0                          
Nasdaq Omx                            
Description Of Business                            
Purchase consideration paid in cash             $ 750,000,000.0              
Period for expected payment under Common stock transaction (years)             15 years              
Nasdaq Omx | Maximum                            
Description Of Business                            
Shares received from transaction (in shares) | shares           992,247                
BGC Partners Inc | Nasdaq Omx | Maximum                            
Description Of Business                            
Expected payment of shares under common stock transaction (in shares) | shares             14,883,705              
BGC Partners Inc | Nasdaq Omx | Minimum                            
Description Of Business                            
Gross revenue on expected payment per year under common stock transaction             $ 25,000,000.0              
Newmark OpCo | RBC                            
Description Of Business                            
Exchangeable preferred limited partnership units issued (in shares)           $ 150,000,000.0               $ 175,000,000.0
Proceeds from issuance of EPUs                 $ 266,100,000          
Exchangeable preferred limited partnership units, number of tranches | tranche           4                
Newmark Holdings, L.P. | Limited Partnership Units | Employees                            
Description Of Business                            
Shares redeemed or exchanged (shares) | shares   8,300,000                        
Newmark Holdings, L.P. | Limited Partnership Units | Independent Contractors                            
Description Of Business                            
Shares redeemed or exchanged (shares) | shares   23,200,000                        
BGC Holdings, L.P. | Limited Partnership Units | Employees                            
Description Of Business                            
Shares redeemed or exchanged (shares) | shares   8,000,000.0                        
BGC Holdings, L.P. | Limited Partnership Units | Independent Contractors                            
Description Of Business                            
Shares redeemed or exchanged (shares) | shares   17,400,000