Leases Leases (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Lease of facilities and furniture maximum duration		15 years
Operating lease, right-of-use asset	$ 230,474	$ 230,474	$ 243,700
Operating leases, rent expense, net	$ 14,000	$ 47,200
Operating lease, weighted average discount rate, percent	3.40%	3.40%
Operating lease, weighted average remaining lease term	8 years 7 months 6 days	8 years 7 months 6 days
Lease liability payments due within twelve months	$ 14,250	$ 14,250
Lessee, operating lease, liability, payments, due year two	45,536	45,536
Lessee, operating lease, liability, payments, due year three	42,202	42,202
Lessee, operating lease, liability, payments, due year four	36,483	36,483
Lessee, operating lease, liability, payments, due year five	30,903	30,903
Lessee, operating lease, liability, payments, due after year five	124,176	124,176
Lessee, operating lease, liability, payments, due	293,550	293,550
Lessee, operating lease, liability, undiscounted excess amount	(39,431)	(39,431)
Operating lease, liability	$ 254,119	$ 254,119	$ 264,600