Leases - Summary of Lease Cost and Cash Flow Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lease Cost
Operating lease cost	$ 3,067	$ 2,735	$ 8,969	$ 8,850
Short-term Lease, Cost	2,465	2,899	6,293	9,384
Finance Lease Cost:
Amortization of leased assets	4,109,000	4,287,000	16,506,000	14,078,000
Finance Lease, Interest Expense	927,000	1,210,000	2,852,000	3,459,000
Total finance lease cost	5,036,000	5,497,000	19,358,000	17,537,000
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	5,850	5,634	16,201	18,234
Financing cash flows from finance leases	$ 8,557,000	$ 4,744,000	$ 20,171,000	$ 20,210,000