Accounts Receivable, Net - Schedule of Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning of period balance	$ (2,168)
(Provision for) / recovery of expected credit losses	(54)	$ (32)
End of period balance	(2,153)
Alarm.com and Certain Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning of period balance	(2,035)	(4,442)
(Provision for) / recovery of expected credit losses	(155)	(36)
Write-offs	68	808
End of period balance	(2,122)	(3,670)
All Other Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning of period balance	(133)	(254)
(Provision for) / recovery of expected credit losses	101	4
Write-offs	1	8
End of period balance	$ (31)	$ (242)