Leases (Narrative) (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease renewal term	5 years			5 years
Lease asset impairments and other charges		$ 2,100,000	$ 0	$ 9,786,000	$ 0
Sublease income	$ 400,000		$ 900,000	2,200,000	$ 2,400,000
Estimated aggregate sublease income to be received in the future	3,200,000			$ 3,200,000
Building
Lessee, Lease, Description [Line Items]
Lease asset impairments and other charges	9,800,000
Leasehold Improvements
Lessee, Lease, Description [Line Items]
Lease asset impairments and other charges	$ 3,600,000
Minimum
Lessee, Lease, Description [Line Items]
Operating lease terms	3 years			3 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease terms	5 years			5 years