Earnings per Share - Summary of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 16, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 16, 2019
Numerator [Abstract]
Net loss	$ (336,234)	$ (43,482)	$ (387,564)		$ (245,548)	$ (440,479)
Less: Net income attributable to SDC Financial prior to the Reorganization Transactions and net loss attributable to noncontrolling interests subsequent to the Reorganization Transactions	$ (247,938)	(30,892)	(299,268)	$ (51,330)	(176,909)	(352,183)	$ (104,245)
Net loss attributable to SDC Inc. - basic		(12,590)	(88,296)		(68,639)	(88,296)
Add: Reallocation of net loss attributable to noncontrolling interests after the Reorganization Transactions from the assumed exchange of LLC Units for Class A common stock		(30,892)	(247,938)		(176,909)	(247,938)
Net loss attributable to SDC Inc. - diluted		$ (43,482)	$ (336,234)		$ (245,548)	$ (336,234)
Denominator [Abstract]
Weighted average shares of Class A common stock outstanding - basic (in shares)		111,703,080	99,533,877		108,459,488	99,533,877
Add: Dilutive effects as shown separately below (in shares)		273,969,597	279,474,505		276,429,361	279,474,505
Weighted average shares of Class A common stock outstanding - diluted (in shares)		385,672,677	379,008,382		384,888,849	379,008,382
Earnings per share of Class A common stock, basic (in USD per share)		$ (0.11)	$ (0.89)		$ (0.63)	$ (0.89)
Earnings per share of Class A common stock, diluted (in USD per share)		$ (0.11)	$ (0.89)		$ (0.64)	$ (0.89)