Redeemable Preferred Stocks - Summary of Redeemable Preferred Stock (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stockholders Equity [Line Items]
Accumulated dividends	$ 35,182	$ 30,729	$ 26,840
Series E Redeemable Preferred Stock [Member]
Stockholders Equity [Line Items]
Beginning balance	$ 234,893
Beginning balance, shares	139,768
Accretion relating to liquidation preference on preferred stock	$ 943
Accretion for discount and issuance costs on preferred stock	1,083
Accumulated dividends	35,182	30,729	$ 26,840
Ending balance	$ 272,101	$ 234,893
Ending balance, shares	139,768	139,768
Series F Redeemable Preferred Stock [Member]
Stockholders Equity [Line Items]
Beginning balance, shares	1
Ending balance, shares	1	1