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, 2020	Dec. 31, 2019
Minimum
Indefinite-lived Intangible Assets [Line Items]
Discount rates	20.00%	19.00%
Customer attrition rates	23.00%	5.00%
Maximum
Indefinite-lived Intangible Assets [Line Items]
Discount rates	23.00%	24.00%
Customer attrition rates	41.00%	37.00%
Weighted Average
Indefinite-lived Intangible Assets [Line Items]
Discount rates	22.00%	24.00%
Customer attrition rates	29.00%	6.00%