Shareholders' Equity (Summary of Restricted Stock and Goal-Based Stock Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested beginning, Shares	1,085	1,301	1,476
Granted, Shares	312	390	299
Vested, Shares	(356)	(596)	(617)
Cancelled and forfeited, Shares	(34)	(10)	(25)
Converted from goal-based stock to restricted stock, Shares			168
Nonvested ending, Shares	1,007	1,085	1,301
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Nonvested beginning, Weighted Average Grant Date Fair Value	$ 44.46	$ 37.37	$ 38.20
Granted, Weighted Average Grant Date Fair Value	$ 54.70	$ 51.14	$ 43.68
Vested, Weighted Average Grant Date Fair Value	$ 39.00	$ 33.31	$ 40.72
Cancelled and forfeited, Weighted Average Grant Date Fair Value	$ 51.11	$ 42.99	$ 36.29
Converted from goal-based stock to restricted stock, Weighted - average Grant Date Fair Value			$ 30.99
Nonvested ending, Weighted Average Grant Date Fair Value	$ 49.35	$ 44.46	$ 37.37
Goal-Based Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested beginning, Shares	4	12	161
Granted, Shares	4	1	3
Vested, Shares	(2)	(9)	(20)
Cancelled and forfeited, Shares	(1)		(132)
Converted from goal-based stock to restricted stock, Shares	1
Nonvested ending, Shares	5	4	12
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Nonvested beginning, Weighted Average Grant Date Fair Value	$ 45.60	$ 39.19	$ 31.79
Granted, Weighted Average Grant Date Fair Value	$ 54.17	$ 52.48	$ 43.54
Vested, Weighted Average Grant Date Fair Value	$ 43.54	$ 37.46	$ 34.62
Cancelled and forfeited, Weighted Average Grant Date Fair Value	$ 43.54		$ 30.99
Nonvested ending, Weighted Average Grant Date Fair Value	$ 53.85	$ 45.60	$ 39.19