Business Combination (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019		Dec. 31, 2018
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	$ 812.4	[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