General form of registration statement for all companies including face-amount certificate companies

Goodwill - Narrative (Details)

v3.19.3.a.u2
Goodwill - Narrative (Details) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended 8 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2018
Sep. 30, 2019
Dec. 31, 2018
Jun. 30, 2018
Aug. 31, 2019
Sep. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
May 31, 2018
Goodwill [Line Items]                    
Loss on goodwill impairment   $ 0     $ 0 $ 214,400 $ 563,549 $ 0 $ 0  
Reporting unit reallocated from segment             0      
MONI                    
Goodwill [Line Items]                    
Loss on goodwill impairment       $ 214,400     214,400      
Reporting unit reallocated from segment $ 313,102           313,102      
LiveWatch                    
Goodwill [Line Items]                    
Loss on goodwill impairment             0      
Reporting unit reallocated from segment $ 36,047           36,047      
Brinks Home Security                    
Goodwill [Line Items]                    
Loss on goodwill impairment     $ 349,149       349,149      
Reporting unit reallocated from segment             $ (349,149)      
Valuation, Income Approach | Measurement Input, Discount Rate | MONI                    
Goodwill [Line Items]                    
Percentage of fair value in excess of carrying amount                   8.50%
Valuation, Income Approach | Measurement Input, Discount Rate | LiveWatch                    
Goodwill [Line Items]                    
Percentage of fair value in excess of carrying amount                   8.50%
Valuation, Income Approach | Measurement Input, Discount Rate | Brinks Home Security                    
Goodwill [Line Items]                    
Percentage of fair value in excess of carrying amount     8.50%       8.50%