Net Federal Income Taxes and Cash Interest Paid (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Cash Flow Information [Abstract]
Federal income taxes paid	$ 613	$ 426	$ 54
Interest paid	$ 0	$ 5,125	$ 10,340