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Seasonal Financing and Debt - Schedule of Long-term Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2019
Debt Instrument [Line Items]
Gross, long-term debt	$ 2,900,000	$ 2,900,000
Debt issuance costs and debt discount	(53,249)	(48,277)
Long-term debt	2,846,751	2,851,723
Less: current portion	0	0
Total long-term debt	2,846,751	2,851,723
2010 Senior Notes due October 2020 and October 2040 \| Senior Notes
Debt Instrument [Line Items]
Gross, long-term debt	$ 250,000	$ 500,000
Weighted average interest rate	5.31%	5.28%
2011 Senior Notes due November 2041 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	5.45%
Gross, long-term debt	$ 300,000	$ 300,000
2013 Senior Notes due March 2023 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	3.15%
Gross, long-term debt	$ 250,000	250,000
2016 Senior Notes due August 2021 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	2.35%
Gross, long-term debt		350,000
2017/2018 Senior Notes due December 2025 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	6.75%
Gross, long-term debt	$ 1,500,000	1,500,000
2019 Senior Notes due December 2027 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	5.875%		5.875%
Gross, long-term debt	$ 600,000	$ 0
Minimum \| 2010 Senior Notes due October 2020 and October 2040 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	4.35%
Maximum \| 2010 Senior Notes due October 2020 and October 2040 \| Senior Notes
Debt Instrument [Line Items]
Interest Rate	6.20%