Stockholders' Equity - Additional Information (Details) shares in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020 vote $ / shares shares	Dec. 31, 2020 $ / shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Number of shares issued during period	1.7
Number of units redeemed in exchange for common stock (in shares)	1.7
Preferred stock, par value (in usd per share) | $ / shares	$ 1	$ 1	$ 1
Number of votes entitled from each stock held of preferred stock | vote	1
Percentage of restriction on ownership (more than)		3.90%
TIER | Common Stock
Class of Stock [Line Items]
Number of shares issued in merger			41.6