Stock Transactions and Unit Redemptions - Gross Unit Redemptions and Share Repurchases of Class A Common Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock Transactions Parenthetical Disclosures [Abstract]
Redemptions, Number of Units	235,000
Repurchases, Number of Shares		233,172
Total Number of Units Redeemed or Shares Repurchased	235,000
Redemptions, Weighted Average Price Paid per Unit or Share	$ 4.30
Total Redemptions and Repurchases, Weighted Average Price Paid per Unit or Shares	$ 4.30
Total Redemptions and Repurchases, Approximate Dollar Value of Units and Shares That May Yet Be Redeemed/Purchased Under the Program	$ 255,678