Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1,	$ 24,400	$ 25,500
Gross increases for tax positions of prior years	800	1,200
Gross increases for tax positions of current year	2,700	4,000
Decreases due to settlements and other prior year tax positions	(4,200)	(5,600)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	10,500	700
Balance at December 31,	13,200	24,400
Reserves related to potential interest and penalties at December 31,	1,200	3,700
Unrecognized tax benefits at December 31,	$ 14,400	$ 28,100