Fair Value of Financial Instruments - Summary of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Liabilities:
Debt at fair value	$ 146,953	$ 157,747
Total	146,953	157,747
Level 1
Liabilities:
Debt at fair value	0	0
Total	0	0
Level 2
Liabilities:
Debt at fair value	146,953	157,747
Total	146,953	157,747
Level 3
Liabilities:
Debt at fair value	0	0
Total	$ 0	$ 0