Debt - Debt Acquired in Acquisition (Details)		6 Months Ended
	Sep. 16, 2008 USD ($) subsidiary	Jun. 25, 2017 USD ($)	Dec. 25, 2016 USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount		$ 374,100,000	$ 437,300,000
Carrying Amount		370,500,000	$ 432,000,000
10-year term loan
Debt Instrument [Line Items]
Debt instrument, face amount	$ 10,000,000.0
Maturity period	10 years
Number of subsidiaries acquired | subsidiary	1
Carrying Amount		1,300,000
Quarterly installment payment - principal		$ 300,000
LIBOR rate | 10-year term loan
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.50%