Leases (Supplemental Information Relating to Operating Leases) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Leases [Abstract]
Lease expense incurred: Operating lease cost	$ 8,258	$ 6,031	$ 16,148	$ 11,218
Operating lease right of use assets	151,653	69,869	151,653	69,869	$ 161,435
Operating lease liabilities	163,690	77,270	163,690	77,270	$ 169,909
Operating cash flows from operating leases	$ (4,917)	$ (4,495)	$ (9,836)	$ (8,926)
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	4.10%		4.10%		3.91%