Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 1,025	$ (243)
Unrecognized tax benefits	5,400		$ 5,300
Expected reduction in unrecognized tax benefits	$ 3,400