Derivative Instruments - (Details Textual) $ in Thousands, lb in Millions, gal in Millions, BTU in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) BTU lb gal
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil covered under the open commodity derivative contracts (in gallons) | gal	54.6
Soybean oil covered under the open commodity derivative contracts (in pounds) | lb	120.4
Natural gas covered under the open commodity derivative contracts (in BTUs) | BTU	2.1
Net position	$ 3,116
Commodity contract derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Collateral associated with commodity-based derivatives	$ 9,256