Income Taxes - Significant Components of Deferred Tax Assets and Liabilities - (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Investment in partnership	$ 144,688	$ 93,089
Net operating loss carryforwards	58,513	21,283
Deferred tax assets, gross	203,201	114,372
Less: valuation allowance	0	0
Deferred tax assets	203,201	114,372
Deferred tax liabilities:
Other	0	0
Deferred tax liabilities	0	0
Net deferred tax assets	$ 203,201	$ 114,372