Share-Based Compensation and Capital Stock Summary Of Activity Related To PVRSU Grants (Details) (Performance Vested Restricted Stock Units [Member], USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Performance vested restricted stock units granted at target	6,137	0	100,046	25,036
Weighted average grant date fair value per share	$ 32.59	$ 0.00	$ 35.68	$ 41.25
Aggregate grant date fair value ($000)	$ 200	$ 0	$ 3,570	$ 1,033
Stock units forfeited	0	0	57,176	41,512
Requisite service period	41 months	0 months		36 months
Minimum [Member]
Requisite service period			36 months
Maximum [Member]
Requisite service period			60 months