Retirement Plans (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) plan	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) plan	Sep. 30, 2018 USD ($)
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension cost (income)	$ 100,000	$ 100,000	$ 200,000	$ 200,000
Number of plans | plan	3		3
Contributions to defined benefit pension plans			$ 200,000
UK Plan | United Kingdom Subsidiary [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension cost (income)	$ (450,000)	$ (747,000)	(1,397,000)	$ (2,327,000)
Contributions to defined benefit pension plans			3,100,000
Anticipated additional contribution	$ 1,200,000		$ 1,200,000