Employee Benefit Plans (Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets, Other Postretirement Benefit Plans) (Details) (Other Postretirement Benefit Plan [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 13,396	$ 12,958
Realized gains (losses)	384	182	929
Fair value of plan assets at end of year	14,728	13,396	12,958
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	1,217	1,194	1,130
Realized gains (losses)	0	0	68
Unrealized gains (losses)	124	31	56
Fair value of plan assets at end of year	1,341	1,217	1,194
Common Collective Trusts [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	9	0
Realized gains (losses)	0	0	68
Unrealized gains (losses)	0	(1)	1
Fair value of plan assets at end of year	0	0	9
Venture Capital Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	1	1
Realized gains (losses)	0	0	0
Unrealized gains (losses)	0	(1)	0
Fair value of plan assets at end of year	0	0	1
Multi-strategy hedge funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at end of year	1,341	1,217
Multi-strategy hedge funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	1,217	1,184	1,129
Realized gains (losses)	0	0	0
Unrealized gains (losses)	124	33	55
Fair value of plan assets at end of year	1,341	1,217	1,184
Defined Benefit Plan, Purchases [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	0	552
Defined Benefit Plan, Purchases [Member] | Common Collective Trusts [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	0	552
Defined Benefit Plan, Purchases [Member] | Venture Capital Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	0	0
Defined Benefit Plan, Purchases [Member] | Multi-strategy hedge funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	0	0
Defined Benefit Plans, Sales and Settlements [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	(8)	(612)
Defined Benefit Plans, Sales and Settlements [Member] | Common Collective Trusts [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	(8)	(612)
Defined Benefit Plans, Sales and Settlements [Member] | Venture Capital Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	0	0	0
Defined Benefit Plans, Sales and Settlements [Member] | Multi-strategy hedge funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Purchases, issuances, and settlements	$ 0	$ 0	$ 0