Shareholder's Equity (Schedule of Stock Option Activity (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Shareholders' Equity
Outstanding at beginning of period, Number of Shares	270,464
Options exercised, Number of Shares	(19,921)
Options terminated, Number of Shares	0
Outstanding at end of period, Number of Shares	250,543	270,464
Vested or expected to vest at end of period, Number of Shares	250,543
Exercisable at end of period, Number of Shares	250,543
Outstanding at beginning of period, Weighted Average Exercise Price	$ 23.16
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 24.49
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 0
Outstanding at end of period, Weighted Average Exercise Price	$ 23.05	$ 23.16
Vested or expected to vest at end of period, weighted average exercise price	$ 23.05
Exercisable at end of period, Weighted Average Exercise Price	$ 23.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term, Period Start	2 years 2 months 12 days	2 years 6 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term, Period End	2 years 2 months 12 days	2 years 6 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	2 years 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	2 years 2 months 12 days