Leases (Supplemental Information Relating to Operating Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Lease expense incurred: Operating lease cost	$ 29,822	$ 21,471
Operating lease right of use assets	$ 139,835	$ 152,978	$ 60,325
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets	Other assets
Operating lease liabilities	$ 155,144	$ 160,387	$ 66,551
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities	Other liabilities
Operating cash flows from operating leases	$ (18,411)	$ (17,617)
Weighted average remaining operating lease term	12 years 6 months	12 years 9 months 18 days
Weighted average discount rate on operating leases	4.02%	3.91%