Goodwill and Other Intangible Assets - Changes in Net Carrying Amount of Contracts and Related Customer Relationships (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period	$ 5,336,645
Amortization	(306,956)	$ (306,307)
Balance as of end of period	5,142,283
Customer-Related Intangible Assets
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period	4,091,545
Amortization	(284,811)
Balance as of end of period	3,919,328
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Customer contract additions, net of dealer charge-backs	17,400
Customer Contracts
Finite-lived Intangible Assets [Roll Forward]
Customer contract additions, net of dealer charge-backs	$ 95,194

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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