Summary of Significant Accounting Policies - Significant Estimates Used by Management in Determining Fair Values of Customer Relationships Acquired (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Indefinite-lived Intangible Assets [Line Items]
Discount rates	22.00%
Customer attrition rates	25.00%
Minimum
Indefinite-lived Intangible Assets [Line Items]
Discount rates		19.00%
Customer attrition rates		10.00%
Maximum
Indefinite-lived Intangible Assets [Line Items]
Discount rates		25.00%
Customer attrition rates		43.00%
Weighted Average
Indefinite-lived Intangible Assets [Line Items]
Discount rates		20.00%
Customer attrition rates		13.00%