Intangible Assets, Net - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Definite-lived intangible assets:
Investment contracts and other	$ 609,958	$ 489,570
Accumulated amortization	(272,650)	(252,822)
Definite-lived intangible assets, net	337,308	236,748
Indefinite-lived intangible assets	43,516	43,516
Total intangible assets, net	$ 380,824	$ 280,264	$ 295,325	$ 310,391

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

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

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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 assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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