Summary of Critical and Significant Accounting Policies - Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Redeemable noncontrolling interest	$ 37,410	$ 35,475	$ 35,475
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at January 1,	37,410	35,475	39,206
Reclassifications due to change in redemption value and other	(4,299)	2,008	1,164
Redemptions	(872)	(73)	(4,895)
Balance at December 31,	$ 32,239	$ 37,410	$ 35,475