Debt, Commitments and Contingencies - Legal Proceedings (Details) - Pending Litigation - numberOfPatents							1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 22, 2022	Jan. 10, 2022	Jul. 28, 2021	Jul. 22, 2021	Feb. 25, 2021	Jun. 02, 2015	Oct. 31, 2019	Mar. 31, 2022	Dec. 31, 2019
Vivint, Inc. vs. Alarm.com Holdings, Inc
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company						6
Number of patents found to be unpatentable									5
Number of patents allegedly infringed by elements in solution						1
EcoFactor, Inc. vs. Alarm.com Holdings, Inc.
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company		5					2
Number of patents under ex parte reexamination								2
Number of patents under reexamination								3
Causam Enterprises, Inc vs Alarm.com Holdings, Inc
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company				4
Causam Enterprises, Inc vs Alarm.com Holdings, Inc and EnergyHub, Inc
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company			4
Vivint, Inc vs ADT LLC
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company	5
Patents under inter partes review	2
Patents pending a decision after review	3
Vivint, Inc vs ADT LLC | Minimum
Loss Contingencies [Line Items]
Number of patents allegedly infringed upon by the company					1