Description of Company and Summary of Significant Accounting Policies - COVID 19 (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle
Deferred credits and other liabilities	$ 83,055	$ 67,682
CARES Act, Deferral Of Social Security Tax
New Accounting Pronouncements or Change in Accounting Principle
Deferred credits and other liabilities	$ 12,700

Carrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income after one year or beyond the normal operating cycle, if longer and noncurrent obligations not separately disclosed in the balance sheet (other liabilities, noncurrent).

No definition available.

Name:	us-gaap_DeferredCreditsAndOtherLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant