Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions		6 Months Ended
	Jul. 12, 2019	Jun. 30, 2019	Oct. 26, 2018	Mar. 06, 2018
Dividends Payable [Line Items]
Quarterly cash dividend declared		$ 0.15
Dividend declared date		Jun. 13, 2019
Dividend record date		Jun. 28, 2019
Dividends paid		$ 12.1
Dividend paid date		Jul. 12, 2019
Equity Class Of Treasury Stock [Line Items]
Repurchase of common shares program authorized amount			$ 100.0	$ 250.0
Repurchase of common shares remaining authorized amount		$ 101.5
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends paid	$ 5.7