Derivative Instruments (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Derivative
Derivative Instruments in Hedges, Net Investment in Foreign Operations, Assets, Fair Value, Net	$ 9,500,000
Loss on ineffective hedge	0	$ 700,000
Amount of derivaitve cash flow hedge to be repcognized in the next 12 months	8,400,000	$ 600,000
Foreign currency derivatives
Derivative
Derivative, Notional Amount	49,900,000		$ 19,600,000
Commodity derivative contracts
Derivative
Derivative, Notional Amount	130,200,000		142,100,000
Unrealized (loss) gain in other comprehensive income	$ 20,500,000		$ 10,700,000