Leases - Lease Cost Finance And Operating Leases (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	[1]	$ 5,760	$ 5,225	$ 16,972	$ 15,266
Finance lease cost
Amortization of leased assets	[2]	856	1,144	2,762	3,955
Interest on finance lease obligations		64	84	207	268
Total lease costs		$ 6,680	$ 6,453	$ 19,941	$ 19,489

[1] Includes variable lease costs of $0.6 million and $0.5 million for the three months ended September 30, 2020 and 2019, respectively, and $1.9 million and $1.5 million for the nine months ended September 30, 2020 and 2019, respectively, and short-term lease costs of $0.2 million for each of the three months ended September 30, 2020 and 2019, respectively, and $0.6 million for each of the nine months ended September 30, 2020 and 2019, respectively.

[2] Includes variable lease costs of $0.2 million for each of the three months ended September 30, 2020 and 2019, respectively, and $0.6 million and $0.7 million for the nine months ended September 30, 2020 and 2019, respectively.