Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating lease cost
Operating lease expense	$ 1,180	$ 1,169	$ 3,534	$ 3,448
Variable lease expense	1,066	845	2,664	2,380
Finance lease cost
Amortization of right-of-use assets	88	51	236	101
Interest on lease liabilities	245	196	722	392
Total lease expense	2,579	2,261	7,156	6,321
Other information
Operating cash flows outflows related to operating leases	1,440	1,313	5,412	5,461
Financing cash flows outflows related to financing leases	143	107	3,310	249
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 0	$ 0	$ 7,212	$ 14,294
Weighted-average remaining lease term (excluding renewal options) - operating leases	48 years 10 months 24 days	49 years 8 months 12 days	48 years 10 months 24 days	49 years 8 months 12 days
Weighted-average remaining lease term (excluding renewal options) -finance leases	64 years 8 months 12 days	70 years 1 month 6 days	64 years 8 months 12 days	70 years 1 month 6 days
Weighted-average discount rate - operating leases	5.70%	5.70%	5.70%	5.70%
Weighted-average discount rate - finance leases	5.40%	5.50%	5.40%	5.50%