Property and Equipment, net - Lease and maturity of lease liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Lease liabilities
Lessee, Operating Lease, Existence of Residual Value Guarantee [true false]	false
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Operating lease liabilities, current	$ 11,659		$ 12,674
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current		Accrued Liabilities, Current
Finance lease liabilities, current	$ 2,317		$ 2,284	[1]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Finance lease liabilities, current		Finance lease liabilities, current
Operating lease liabilities, noncurrent	$ 13,193		$ 14,188
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other Liabilities, Noncurrent		Other Liabilities, Noncurrent
Finance lease liabilities, noncurrent	$ 32,154		$ 32,573	[1]
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Finance lease liabilities, noncurrent		Finance lease liabilities, noncurrent
Total lease liabilities	$ 59,323		$ 61,719
Cash paid for operating lease liabilities	3,500	$ 3,200
Cash paid for financing lease liabilities in operating cash flows	600	200
Cash paid for financing lease liabilities in financing cash flows	$ 573	187
Maturity of our finance lease liabilities
Weighted average lease term, finance leases	14 years 1 month 6 days
Weighted average lease term, operating leases	4 years 10 months 24 days
Weighted average discount rate, finance leases	3.80%
Weighted average discount rate, operating leases	5.50%
Expense related to our operating leases	$ 3,500	3,200
Amortization on our finance lease right-of-use assets	600	600
Interest expense on finance lease liabilities	$ 300	$ 300

[1] The condensed consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date.