Retirement Plans (Fair Value of Pension Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Jan. 02, 2016	Dec. 27, 2014
Retirement Plans [Line Items]
Fair value of plan assets	$ 238,343	$ 247,519
Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	238,343	247,519	$ 267,635
Fair Value, Measurements, Recurring [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	194,533	197,238
Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	7,624	12,306
Fair Value, Measurements, Recurring [Member] | Equity [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	123,352	120,953
Fair Value, Measurements, Recurring [Member] | Fixed income [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	62,188	62,490
Fair Value, Measurements, Recurring [Member] | Other [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	1,369	1,489
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	146,884	145,756
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Cash and cash equivalents [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	7,624	12,306
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Equity [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	123,352	120,953
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Fixed income [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	15,908	12,497
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	47,649	51,482
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Cash and cash equivalents [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Equity [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Fixed income [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	46,280	49,993
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	1,369	1,489
Nonrecurring fair value [Member] | Alternative investments [Member] | Pensions [Member]
Retirement Plans [Line Items]
Fair value of plan assets	$ 43,810	$ 50,281