Operating Leases (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Right-of-use assets	$ 725,800
Lease liabilities	707,039
Operating lease costs	90,354
Occupancy and Equipment Rental [Member]
Lessee Lease Description [Line Items]
Operating lease costs	$ 87,200
Minimum [Member] | Office Space and Office Equipment [Member]
Lessee Lease Description [Line Items]
Operating leases remaining lease term	1 year
Maximum [Member] | Office Space and Office Equipment [Member]
Lessee Lease Description [Line Items]
Operating leases remaining lease term	11 years