Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended
	Jan. 01, 2020	Jan. 01, 2019	Aug. 31, 2017	Mar. 31, 2020	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity securities, transferred security, at carrying value				$ 0	$ 11,544
Retained earnings				44,331	1,049
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses	$ 57,442
Retained earnings	$ 44,331			$ 44,331	$ 1,049
Accounting Standards Update 2017-12 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity securities, transferred security, at carrying value			$ 11,544
Decrease in AOCI due to transfer of held to maturity securities			$ 1,098
Accounting Standards Update 2018-10 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net lease assets		$ 67,040
Net lease liabilities		70,692
Effect on retained earnings		$ 1,049