Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 17,882	$ 4,572
Weighted average shares outstanding - basic and diluted (in shares)	5,122,206	5,118,698
Net income per common share - basic and diluted (in usd per share)	$ 3.49	$ 0.89