Variable Interest Entities - Summary of Information about Variable Interests (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Carrying Amount - Assets
Total net carrying value	$ 885,217	$ 896,692
Securrency Inc [Member]
Carrying Amount - Assets
Preferred stock – Series A Shares	8,349	8,112
Preferred stock – Series B Shares	5,500
Variable Interest Entity, Not Primary Beneficiary [Member]
Carrying Amount - Assets
Total net carrying value	13,849	8,112
Maximum exposure to loss	$ 13,849	$ 8,112