Pension and Other Retirement Plans - Pension Plan Assets by Asset Category (Details) - Pension Plans - USD ($) $ in Thousands		Dec. 31, 2016		Dec. 31, 2015		Dec. 28, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		$ 1,545,862		$ 1,530,898		$ 1,655,257
Total pension plan assets measured at fair value		1,096,386		1,120,987
Defined benefit plan, fair value of plan assets, measured using net asset value		424,875	[1]	385,705	[2]
Contract value of pension plan assets		24,601		24,206
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets measured at fair value		575,884		585,719
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets measured at fair value		520,502		535,268
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets measured at fair value		0		0
Registered investment companies
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		575,884		585,719
Registered investment companies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		575,884		585,719
Registered investment companies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Registered investment companies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Common/collective trusts
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		16,060		16,432
Common/collective trusts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Common/collective trusts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		16,060		16,432
Common/collective trusts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		200,782		167,969
U.S. government securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
U.S. government securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		200,782		167,969
U.S. government securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		264,451		246,739
Corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		264,451		246,739
Corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Mortgage-backed and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		30,961		29,473
Mortgage-backed and asset-backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Mortgage-backed and asset-backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		30,961		29,473
Mortgage-backed and asset-backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Other alternative investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		(9,155)	[3]	26,582	[4]
Other alternative investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[3]	0	[4]
Other alternative investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		(9,155)	[3]	26,582	[4]
Other alternative investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0	[3]	0	[4]
Pooled separate account
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		17,403		18,221
Pooled separate account | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Pooled separate account | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		17,403		18,221
Pooled separate account | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0		0
Loan fund limited partnership
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets				29,852
Loan fund limited partnership | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets				0
Loan fund limited partnership | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets				29,852
Loan fund limited partnership | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets				0
Pending net purchases
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	[4]	$ (58,000)		$ (11,000)

[1] (2) In accordance with ASU 2015-07, certain common/collective trusts, the 103-12 investment entity, the international equity limited partnership, real estate, private equity and venture capital limited partnerships that are measured at fair value using the NAV per share practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in the table above are intended to permit reconciliation of the fair value hierarchy to the total value of plan assets.

[2] (2) In accordance with ASU 2015-07, certain common/collective trusts, the 103-12 investment entity, the international equity limited partnership, real estate, private equity and venture capital limited partnerships that are measured at fair value using the NAV per share practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in the table above are intended to permit reconciliation of the fair value hierarchy to the total value of plan assets.

[3] Other includes pending net security purchases of $58 million.

[4] Other includes pending net security purchases of $11 million.