Derivative Financial Instruments (Schedule of Offsetting of Derivative Assets) (Details) - USD ($) $ in Thousands	Jul. 01, 2018	Dec. 31, 2017
Offsetting of Derivative Assets [Line Items]
Gross Amounts of Recognized Assets	$ 3,824	$ 1,799
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0	0
Net Amounts Of Assets Presented in the Condensed Consolidated Balance Sheets	3,824	1,799
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Financial Instruments	(507)	(1,799)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Cash Collateral Pledged	0	0
Net Amount	3,317	0
Bank of America
Offsetting of Derivative Assets [Line Items]
Gross Amounts of Recognized Assets	2,181	1,664
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0	0
Net Amounts Of Assets Presented in the Condensed Consolidated Balance Sheets	2,181	1,664
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Financial Instruments	(318)	(1,664)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Cash Collateral Pledged	0	0
Net Amount	1,863	0
Wells Fargo
Offsetting of Derivative Assets [Line Items]
Gross Amounts of Recognized Assets	1,643	135
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0	0
Net Amounts Of Assets Presented in the Condensed Consolidated Balance Sheets	1,643	135
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Financial Instruments	(189)	(135)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets: Cash Collateral Pledged	0	0
Net Amount	$ 1,454	$ 0