Leases (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Feb. 28, 2018 ft²	Jan. 12, 2018 ft²
Operating Leased Assets [Line Items]
Rent expense | $	$ 5.7	$ 6.1	$ 8.1
Photocopiers [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Sep. 30, 2020
Corporate Headquarters [Member]
Operating Leased Assets [Line Items]
Rented area of office space				63,000
Increase in area of real estate property					12,300
Other Rentable Space [Member]
Operating Leased Assets [Line Items]
Rented area of office space				7,000