Stockholders' Equity (Detail) - Class A CMN Stock - USD ($)	3 Months Ended	36 Months Ended
	Mar. 31, 2022	May 01, 2021	Jun. 21, 2021	Mar. 16, 2020	May 01, 2018
Stock Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount				$ 250,000,000
Stock repurchased during period	$ 0
Sales Agreement
Class of Stock [Line Items]
Common stock, shares sold (in shares)		842,412
2021 Sales Agreement
Class of Stock [Line Items]
Common stock, shares sold (in shares)	0
Common stock, shares available to be sold	$ 400,000,000
Maximum | Sales Agreement
Class of Stock [Line Items]
Aggregate offering price of common stock issuable					$ 400,000,000
Maximum | 2021 Sales Agreement
Class of Stock [Line Items]
Aggregate offering price of common stock issuable			$ 400,000