Common Shares And Stock-Based Awards Plans (Summary Of Stock-Based Awards) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares outstanding, shares or units, beginning balance	467	412	303
Granted, shares or units	392	228	246
Vested, shares or units	(209)	(161)	(112)
Forfeited, shares or units	(125)	(12)	(25)
Non-vested shares outstanding, shares or units, ending balance	525	467	412
Non-vested outstanding, weighted-average grant date fair value, beginning balance	$ 21.59	$ 20.33	$ 17.48
Granted, weighted-average grant date fair value	22.71	23.06	22.92
Vested, weighted-average grant date fair value	21.07	20.51	18.34
Forfeited, weighted-average grant date fair value	21.85	21.03	19.99
Non-vested outstanding, weighted-average grant date fair value, ending balance	$ 22.57	$ 21.59	$ 20.33
Performance-Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares outstanding, shares or units, beginning balance	306	274	215
Granted, shares or units	184	85	88
Forfeited, shares or units	(263)	(53)	(29)
Non-vested shares outstanding, shares or units, ending balance	227	306	274
Non-vested outstanding, weighted-average grant date fair value, beginning balance	$ 19.77	$ 18.56	$ 16.78
Granted, weighted-average grant date fair value	21.63	22.93	22.92
Forfeited, weighted-average grant date fair value	19.64	18.57	18.52
Non-vested outstanding, weighted-average grant date fair value, ending balance	$ 21.43	$ 19.77	$ 18.56