Leases (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Jan. 01, 2019
Operating Leased Assets [Line Items]
Option to extend the lease, term	up to 5 years
Option to terminate the lease, term	within 1 year
Lease right of use assets	$ 90,755
Lease liabilities	$ 101,593
Weighted average rate	3.46%			3.47%
Operating lease payments related to extended lease terms		$ 2,300
Lease payments for leases signed, but not yet commenced		$ 1,300
ASU 2016-02 [Member]
Operating Leased Assets [Line Items]
Lease right of use assets			$ 87,800
Lease liabilities			$ 98,700
Minimum [Member]
Operating Leased Assets [Line Items]
Remaining terms of leases under operating lease	1 year
Maximum [Member]
Operating Leased Assets [Line Items]
Remaining terms of leases under operating lease	10 years