Retirement Plans (Components Of Net Periodic Pension Benefit Cost) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension cost (income)	$ 100,000	$ 100,000	$ 200,000	$ 200,000
UK Plan | United Kingdom Subsidiary [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1,925,000	1,959,000	5,968,000	6,103,000
Expected return on plan assets	(2,941,000)	(3,344,000)	(9,121,000)	(10,415,000)
Amortization of unrecognized loss	566,000	638,000	1,756,000	1,985,000
Net periodic pension cost (income)	$ (450,000)	$ (747,000)	$ (1,397,000)	$ (2,327,000)