New Accounting Principles and Recent Accounting Pronouncements - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease assets		$ 598,293	$ 0	[1]		$ 618,100
Operating lease liabilities		92,286	0	[1]		155,500
Operating And Finance Lease Liabilities, Noncurrent						$ 468,400
Reclassification of certain tax effects from accumulated other comprehensive loss		0	(30,237)		$ 0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent | Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of certain tax effects from accumulated other comprehensive loss	$ 28,400
Deferred Loss on Interest Rate Derivative Hedges | Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of certain tax effects from accumulated other comprehensive loss	1,800
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sale and leaseback gain recognized upon adoption of ASC 842, net of tax impact		114,712	0
Reclassification of certain tax effects from accumulated other comprehensive loss		$ 0	$ 30,237		$ 0
Retained Earnings | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change on equity or net assets	$ 160,000

[1] Reclassified to conform with current presentation (see Note E)