Debt (Tables)

12 Months Ended

Dec. 27, 2015

Debt Disclosure [Abstract]

Fair value of long-term debt

Carrying amounts and the related estimated fair values of the Company’s long-term debt financial instruments not measured at fair value on a recurring basis at December 28, 2014 and December 27, 2015 are presented in the following table:

	As of December 28, 2014						As of December 27, 2015
$ in millions	Principal		Carrying Amount		Fair Value		Principal		Carrying Amount		Fair Value
Long-term debt	$	669.8	$	656.4	$	577.1	$	452.7	$	445.1	$	315.2