Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Intangible Assets, by category
Gross Carrying Amount	$ 191,921		$ 191,921		$ 202,162
Accumulated Amortization	108,323		108,323		163,911
Amortization expense for intangible assets	2,395	$ 1,269	5,326	$ 3,868
Estimated amortization expense for next 5 years
2018	7,900		7,900
2019	9,750		9,750
2020	9,250		9,250
2021	8,800		8,800
2022	8,500		8,500
Customer related
Intangible Assets, by category
Gross Carrying Amount	137,498		137,498		153,014
Accumulated Amortization	98,834		98,834		121,385
Patents
Intangible Assets, by category
Gross Carrying Amount	2,590		2,590		5,825
Accumulated Amortization	2,495		2,495		5,700
Technology related
Intangible Assets, by category
Gross Carrying Amount	36,666		36,666		26,131
Accumulated Amortization	1,851		1,851		26,131
Trade names
Intangible Assets, by category
Gross Carrying Amount	9,311		9,311		8,317
Accumulated Amortization	1,754		1,754		4,845
Other
Intangible Assets, by category
Gross Carrying Amount	5,856		5,856		8,875
Accumulated Amortization	$ 3,389		$ 3,389		$ 5,850