Income Taxes - Reconciliation Between Cash and Stock Dividends Paid and Dividends Paid Deduction (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Cash Dividends paid	$ 98,073	$ 180,092	$ 280,714
Stock Dividend due to RVI spin-off	0	0	593,659
Total Dividends	98,073	180,092	874,373
Less: Dividends designated to prior year	(5,133)	(8,383)	(8,383)
Plus: Dividends designated from the following year	5,133	5,133	8,383
Less: Return of capital	(32,946)	(67,063)	(689,544)
Dividends paid deduction	$ 65,127	$ 109,779	$ 184,829