Business Combination (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019		Dec. 31, 2018
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	$ 807.9	[1]	$ 812.4	[2]
Sivomatic [Member]
Business Combination [Abstract]
Total consideration transferred, net of cash acquired	122.5
Additional deferred tax liability	$ 18.8
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable			24.4
Inventories			15.6
Other current assets			0.6
Mineral rights			39.7
Property, plant and equipment			28.3
Goodwill			35.0
Intangible assets			26.4
Total assets acquired			170.0
Current maturity of long term debt			5.7
Accounts payable			9.0
Accrued expenses			5.6
Long term debt			5.3
Non-current deferred tax liability			19.7
Other non-current liabilities			2.2
Total liabilities assumed			47.5
Net assets acquired			122.5
Sivomatic [Member] | Previously Reported [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable			24.4
Inventories			15.6
Other current assets			0.6
Mineral rights			39.7
Property, plant and equipment			28.3
Goodwill			35.0
Intangible assets			26.4
Total assets acquired			170.0
Current maturity of long term debt			5.7
Accounts payable			9.0
Accrued expenses			5.6
Long term debt			5.3
Non-current deferred tax liability			19.7
Other non-current liabilities			2.2
Total liabilities assumed			47.5
Net assets acquired			122.5
Sivomatic [Member] | Increase/(Decrease) [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable			0.0
Inventories			0.0
Other current assets			0.0
Mineral rights			0.0
Property, plant and equipment			0.0
Goodwill			0.0
Intangible assets			0.0
Total assets acquired			0.0
Current maturity of long term debt			0.0
Accounts payable			0.0
Accrued expenses			0.0
Long term debt			0.0
Non-current deferred tax liability			0.0
Other non-current liabilities			0.0
Total liabilities assumed			0.0
Net assets acquired			$ 0.0
Sivomatic [Member] | Trade Names [Member]
Business Combination [Abstract]
Estimated useful life of intangible assets acquired	20 years
Sivomatic [Member] | Customer Relationships [Member]
Business Combination [Abstract]
Estimated useful life of intangible assets acquired	20 years

[1] Unaudited

[2] Condensed from audited financial statements