Business Acquisitions - Table (Details) $ in Thousands, € in Millions, SEK in Millions, AUD in Millions	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 EUR (€)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 AUD	Dec. 31, 2014 SEK	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 AUD	Jun. 30, 2014 USD ($)	Dec. 31, 2010 USD ($)
Business Acquisition [Line Items]
Current Assets	$ 31,151
Finite Lived Customer Lists, Gross	71,454		$ 67,435
Other Finite Lived Intangible Assets, Gross	6,023		5,788
Goodwill	80,804		$ 79,111					$ 77,933
Summit [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price												$ 29,800
Australia [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price										AUD 8.0	$ 7,600
Mining [Member]
Business Acquisition [Line Items]
Intangibles		$ 1,700
Goodwill		100
Present Value of Holdback						AUD (0.3)		(200)
Business Acquisition, Cost of Acquired Entity, Purchase Price		$ 1,900				AUD 2.9		2,400
Binol [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price							SEK 136.5	18,500
ECLI [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price									$ 53,100
Verkol [Member]
Business Acquisition [Line Items]
Current Assets	31,151
Propery, Plant & Equipment	7,941
Finite Lived Customer Lists, Gross	6,146
Finite Lived Trademarks, Gross	5,378
Other Finite Lived Intangible Assets, Gross	219
Goodwill	5,051
Other Long-term Assets	158
Total Assets Purchased	56,044
Other Current Liabilities	(6,720)
Long-term Debt	(2,400)			€ (2.2)	$ (2,400)
Other Non-Current Liabilities	(5,531)
Total Liabilities Assumed	(14,651)
Business Acquisition, Cost of Acquired Entity, Purchase Price, Gross	41,393
Cash Acquired	15,423			14.1	15,400
Business Acquisition, Cost of Acquired Entity, Purchase Price	25,970			€ 37.7	$ 41,400
2014 Acquisitions [Member]
Business Acquisition [Line Items]
Current Assets								12,413
Propery, Plant & Equipment								4,158
Finite Lived Customer Lists, Gross								30,924
Finite Lived Trademarks, Gross								12,606
Other Finite Lived Intangible Assets, Gross								1,127
Goodwill								21,546
Other Long-term Assets								198
Total Assets Purchased								82,972
Other Current Liabilities								(4,562)
Other Non-Current Liabilities								(4,374)
Total Liabilities Assumed								(8,936)
Business Acquisition, Cost of Acquired Entity, Purchase Price, Gross								74,036
Cash Acquired								1,037
Business Acquisition, Cost of Acquired Entity, Purchase Price								$ 72,999
2016 Acquisitions [Member]
Business Acquisition [Line Items]
Current Assets	3,443
Propery, Plant & Equipment	2,574
Finite Lived Customer Lists, Gross	5,041
Finite Lived Trademarks, Gross	2,543
Other Finite Lived Intangible Assets, Gross	127
Goodwill	3,311
Total Assets Purchased	17,039
Other Current Liabilities	(1,198)
Other Non-Current Liabilities	(2,019)
Total Liabilities Assumed	(3,217)
Business Acquisition, Cost of Acquired Entity, Purchase Price, Gross	13,822
Cash Acquired	105
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 13,717