Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective tax rates on continuing operations			45.20%	35.80%	35.20%
Federal statutory income taxes rate (as a percent)			35.00%
Increase to provision for income taxes		$ 9,500	$ 9,500
Income taxes at the federal statutory rate of 35%			35,328	$ 35,371	$ 31,032
Increases (decreases) resulting from—
Net state income taxes			2,838	4,262	3,432
Valuation allowances			91	(1,254)	463
Net unrecognized tax benefits			153	20	(72)
Noncontrolling interests					(2,827)
Nondeductible expenses			1,134	825	751
Stock-based compensation deduction			(1,320)	(885)
Domestic production activities deduction			(2,112)	(2,026)	(1,701)
Corporate tax rate reduction to 21%			9,478
Other			76	(148)	146
Provision for income taxes			$ 45,666	$ 36,165	$ 31,224
Forecast
Federal statutory income taxes rate (as a percent)	21.00%