Leases (Supplemental Information Relating to Operating Leases) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Lease expense incurred: Operating lease cost	$ 8,424	$ 5,384	$ 24,572	$ 16,602
Operating lease right of use assets	149,206		149,206		$ 161,435	$ 69,869
Operating lease liabilities	163,329		163,329		$ 169,909	$ 77,270
Operating cash flows from operating leases	$ (5,047)	$ (5,739)	$ (14,883)	$ (14,665)
Weighted average remaining operating lease term	12 years 3 months 18 days		12 years 3 months 18 days		12 years 7 months 6 days
Weighted average discount rate on operating leases	4.11%		4.11%		3.91%