Acquisition, Restructuring and Other Expense (Restructuring Accrual) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Restructuring accrual
Restructuring accrual, beginning balance	$ 2,643	$ 7,175
Expenses incurred	4,125	5,096
Payments made	(5,428)	(10,447)
Restructuring accrual, ending balance	$ 1,340	$ 1,824