Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jul. 09, 2018	Dec. 31, 2017
Assets:
Goodwill	$ 266,304		$ 237,107
Griswold
Assets:
Accounts receivable, less allowance for doubtful accounts		$ 2,553
Inventory		2,998
Other current assets		154
Property, plant & equipment		7,554
Other intangible assets		34,120
Goodwill		32,305
Total assets		79,684
Liabilities:
Accounts payable		711
Accrued employee benefits and compensation		299
Other accrued liabilities		103
Total liabilities		1,113
Fair value of net assets acquired		$ 78,571