Financial Guarantee Liability - Summary of Changes on Estimated Liability Under Guarantee Liability (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020
Guaranty LIability:
Beginning Balance	$ 32,430	$ 15	$ 15
Provision for expected credit losses	222	14,480	14,700
Ending Balance	$ 32,652	32,430	32,652
Cumulative effect of the credit loss standard adoption, net of tax
Guaranty LIability:
Beginning Balance		$ 17,935	$ 17,935