Financial Instruments and Fair Value Measurement - Additional Information (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Derivative [Line Items]
Gross derivative liability	$ 8,700,000
Gross derivative asset	800,000
Long-term debt, fair value	2,281,700,000		$ 1,891,200,000
Long-term debt, carrying value	2,249,100,000		1,876,600,000
Anticipated reclassification of loss to earnings in the next twelve months	7,300,000
Derivative Contracts Designated as Hedging Instruments | Instruments in a Cash Flow Hedging Relationship | Interest Rate Swap
Derivative [Line Items]
Amounts excluded from the measure of effectiveness	0	$ 0
Amount of ineffectiveness related to changes in the fair value of derivatives	0	0
Derivative Contracts Designated as Hedging Instruments | Instruments in a Cash Flow Hedging Relationship | Commodity Contracts
Derivative [Line Items]
Amounts excluded from the measure of effectiveness	$ 0	0
Percentage of expected natural gas usage hedged, current year	67.00%
Percentage of expected natural gas usage hedged, next fiscal year	29.00%
Derivative Contracts Designated as Hedging Instruments | Instruments in a Cash Flow Hedging Relationship | Forward Exchange Contract
Derivative [Line Items]
Amounts excluded from the measure of effectiveness	$ 0	0
Amount of ineffectiveness related to changes in the fair value of derivatives	0	0
Notional amount of derivative	30,200,000		$ 65,200,000
Amounts forecasted and reclassified into earnings no longer probable	$ 0	$ 0
Derivative Contracts Not Designated as Hedging Instruments | Maximum
Derivative [Line Items]
Foreign currency forward exchange contract, term	3 months		3 months
Derivative Contracts Not Designated as Hedging Instruments | Forward Exchange Contract
Derivative [Line Items]
Notional amount of derivative	$ 65,700,000		$ 45,500,000