Summary of Significant Accounting Policies and New Accounting Pronouncements - New or Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 25, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax expense			$ 19,731	$ 39,315	$ 27,607
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax expense	$ 2,000
Unrecognized components of employee benefit plans, net of tax
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from AOCI			$ (4,471)	$ 254	$ 3,313
Scenario, Forecast | Subsequent Event | New Accounting Pronouncement, Early Adoption, Effect | Unrecognized components of employee benefit plans, net of tax | Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from AOCI		$ 23,000