Goodwill and Other Intangible Assets (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	$ 148,395	$ 148,395
Accumulated amortization and impairment losses	(82,937)	(65,495)
Other intangible assets, Net	65,458	82,900
Licenses
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	10,267	10,267
Accumulated amortization and impairment losses	0	0
Other intangible assets, Net	10,267	10,267
Customer relationships and customer lists
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	95,458	95,458
Accumulated amortization and impairment losses	(42,142)	(33,294)
Other intangible assets, Net	53,316	62,164
Value of business acquired
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	20,200	20,200
Accumulated amortization and impairment losses	(19,527)	(13,467)
Other intangible assets, Net	673	6,733
Software
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	12,230	12,230
Accumulated amortization and impairment losses	(11,938)	(10,188)
Other intangible assets, Net	292	2,042
Patents and intellectual property
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	4,500	4,500
Accumulated amortization and impairment losses	(4,500)	(4,500)
Other intangible assets, Net	0	0
Covenants not-to-compete
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	4,030	4,030
Accumulated amortization and impairment losses	(3,523)	(2,763)
Other intangible assets, Net	507	1,267
Trademarks and trade names
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	1,710	1,710
Accumulated amortization and impairment losses	(1,307)	(1,283)
Other intangible assets, Net	$ 403	$ 427