Leases (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets			$ 44,432		$ 0
Operating lease liabilities			$ 47,091		$ 0
Weighted-average remaining lease term (in years):			4 years 3 months 18 days
Lessee, operating lease, not yet commenced, amount			$ 6,000
Rent expense	$ 4,000	$ 7,600
Accounting Standards Update 2016-02 [Member]
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets				$ 41,000
Operating lease liabilities				43,000
Deferred rent credit				$ 2,000
Minimum [Member]
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term (in years):			1 year
Lessee, operating lease, lease not yet commenced, term of contract			1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term (in years):			8 years
Lessee, operating lease, lease not yet commenced, term of contract			8 years