Income Taxes - Components of Net Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Millions	Dec. 27, 2019	Dec. 28, 2018
Net non-current deferred tax asset:
Total deferred tax assets	$ 15.5	$ 10.2
Non-current deferred tax liability:
Undistributed earnings	(0.5)	(2.5)
Operating lease right-of-use assets	(7.2)
Depreciation	(3.3)	(6.4)
Intangibles	(5.8)
Goodwill	(8.4)	(6.9)
Total deferred tax liabilities	(25.2)	(15.8)
Net deferred tax liabilities	(9.7)	(5.6)
Deferred Tax Assets Noncurrent [Member]
Net non-current deferred tax asset:
Inventory valuation and basis difference	3.4	3.3
State taxes	0.5	0.4
Stock compensation	1.7	1.7
Operating lease liabilities	9.0
Interest expense limitation	5.8	0.1
Intangibles	7.8	6.3
Net operating losses	6.4	2.2
Tax credits	2.2	0.6
Other timing differences	4.5	3.3
Deferred tax assets, gross non-current	41.3	17.9
Valuation allowance	$ (25.8)	$ (7.7)