Summary of Significant Accounting Policies (Additional Cash Flow) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncash or Part Noncash Acquisitions [Line Items]
Accrual for purchases of property and equipment	$ 2,300		$ 1,500
Noncash or Part Noncash Acquisition, Other Assets Acquired	(200)
Total net adjustment	4,000	$ 11,900	38,700
Adjustments to other comprehensive income related to underfunding of pension and SERP plans and changes in fair value of derivative financial instruments, tax	2,500	7,200	23,400
Dividends declared but not yet paid	4,900	4,900	4,300
Earnout payments to former owners	5,617	1,453	3,610
Aerospace acquisition
Noncash or Part Noncash Acquisitions [Line Items]
Earnout payments to former owners	$ 1,400	$ 5,400	$ 1,500