Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Apr. 11, 2019	Mar. 31, 2019	Oct. 26, 2018	Mar. 06, 2018
Dividends Payable [Line Items]
Quarterly cash dividend declared		$ 0.15
Dividend declared date		Mar. 15, 2019
Dividend record date		Mar. 29, 2019
Dividends paid		$ 6.2
Dividend paid date		Apr. 11, 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		$ 140.5
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends paid	$ 5.9