New Accounting Standards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Sep. 27, 2020	Jun. 28, 2020	Jan. 01, 2020	Sep. 29, 2019	Jun. 30, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Finance receivables	$ 7,572,947	$ 7,252,194			$ 7,714,156
Allowance for credit losses on finance receivables	198,581	408,702	$ 411,015		198,576	$ 194,996	$ 189,885
Deferred income taxes	101,204	137,960			132,019
Accrued Liabilities	582,288
Retained earnings	2,193,997	$ 2,148,462			$ 2,238,313
Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Finance receivables				$ 0
Allowance for credit losses on finance receivables	$ 100,604			100,604
Deferred income taxes				22,484
Accrued Liabilities				109
Retained earnings				(78,229)
Cumulative Effect, Period Of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Finance receivables				7,572,947
Allowance for credit losses on finance receivables				299,185
Deferred income taxes				123,688
Accrued Liabilities				582,397
Retained earnings				$ 2,115,768