Share-Based Compensation and Capital Stock Summary Of Activity Related To Restricted Stock Grants (Details) (Restricted Stock [Member], USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-Based Compensation and Capital Stock [Line Items]
Granted - shares	2,853	7,646	149,908	223,045
Weighted average grant date fair value per share (in dollars per share)	$ 52.59	$ 39.24	$ 46.58	$ 37.65
Aggregate grant date fair value	$ 150	$ 300	$ 6,983	$ 8,397
Restricted shares forfeited	13,922	25	18,218	27,953
Vesting service period of shares granted	36 months	36 months
Grant date fair value of shares vested	$ 2,076	$ 94	$ 10,280	$ 8,569
Minimum [Member]
Share-Based Compensation and Capital Stock [Line Items]
Vesting service period of shares granted			12 months	12 months
Maximum [Member]
Share-Based Compensation and Capital Stock [Line Items]
Vesting service period of shares granted			48 months	48 months