Fair Value Measurements Financial Instruments (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Jan. 03, 2021
Series 2019-1 Class A-2-I Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	3.783%	3.783%
Series 2019-1 Class A-2-II Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	4.08%	4.08%
Series 2018-1 Class A-2-I Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	3.573%	3.573%
Series 2018-1 Class A-2-II Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	3.884%	3.884%
Series 2015-1 Class A-2-III Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	4.497%	4.497%
7% debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Interest Rate, Stated Percentage	7.00%	7.00%
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash equivalents	$ 25,035	$ 75,067
Reported Value Measurement | Series 2019-1 Class A-2-I Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	383,000	386,000
Reported Value Measurement | Series 2019-1 Class A-2-II Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	430,875	434,250
Reported Value Measurement | Series 2018-1 Class A-2-I Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	435,375	436,500
Reported Value Measurement | Series 2018-1 Class A-2-II Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	459,563	460,750
Reported Value Measurement | Series 2015-1 Class A-2-III Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	472,500	473,750
Reported Value Measurement | Canadian revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	0	1,962
Reported Value Measurement | 7% debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	84,291	83,998
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash equivalents	25,035	75,067
Estimate of Fair Value Measurement | Series 2019-1 Class A-2-I Notes | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	405,482	409,778
Estimate of Fair Value Measurement | Series 2019-1 Class A-2-II Notes | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	457,201	469,555
Estimate of Fair Value Measurement | Series 2018-1 Class A-2-I Notes | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	445,563	450,381
Estimate of Fair Value Measurement | Series 2018-1 Class A-2-II Notes | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	487,872	491,021
Estimate of Fair Value Measurement | Series 2015-1 Class A-2-III Notes | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	475,949	481,851
Estimate of Fair Value Measurement | Canadian revolving credit facility | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	0	1,962
Estimate of Fair Value Measurement | 7% debentures | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Debt instrument	$ 99,900	$ 98,775