Leases - Summary of Lease Cost and Cash Flow Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lease Cost
Operating lease cost	$ 12,036	$ 11,585
Short-term Lease, Cost	8,055	12,975
Finance Lease Cost:
Amortization of leased assets	23,921,000	21,293,000
Finance Lease, Interest Expense	3,634,000	4,150,000	$ 2,270,000
Total finance lease cost	27,555,000	25,443,000
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	21,348	24,560
Financing cash flows from finance leases	$ 25,984,000	$ 25,975,000