Leases (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets		$ 41,275		$ 0
Operating lease liabilities		$ 43,439		$ 0
Weighted-average remaining lease term (in years):		3 years 10 months 25 days
Lessee, operating lease, not yet commenced, amount		$ 6,500
Rent expense	$ 3,600
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):		7 years
Lessee, operating lease, lease not yet commenced, term of contract		8 years