Financial Instruments and Financial Risk Management - Additional information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Investments All Other Investments [Abstract]
Fair value, assets, level 1 to level 2 transfers, amount	$ 0	$ 0	$ 0
Fair value, assets, level 2 to level 1 transfers, amount	0	0	0
Fair value, liabilities, level 1 to level 2 transfers, amount	0	0	0
Fair value, liabilities, level 2 to level 1 transfers, amount	0	0	0
Fair value, equity, level 1 to level 2 transfers, amount	0	0	0
Fair value, equity, level to level 1 transfers, amount	0	0	0
Fair value, transfers into (out of) level 3	0	0	0
Federally insured limits exceeded amount	5,000,000	5,000,000	10,000,000
Cash held with bank accounts	$ 12,000,000	12,000,000
Maximum credit exposure		$ 13,178,000	$ 37,422,000