Leases - Summary of Lease Cost and Cash Flow Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lease Cost
Operating lease cost	$ 3,180	$ 2,855	$ 6,331	$ 5,902
Short-term Lease, Cost	2,054	2,310	5,099	3,828
Finance Lease Cost:
Amortization of leased assets	5,039,000	6,424,000	10,927,000	12,937,000
Finance Lease, Interest Expense	1,018,000	920,000	1,607,000	1,925,000
Total finance lease cost	6,057,000	7,344,000	12,534,000	14,862,000
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	5,234	5,480	11,635	10,351
Financing cash flows from finance leases	$ 9,365,000	$ 5,713,000	$ 15,028,000	$ 11,614,000