Stock-Based Compensation (Summary of Company's SARs Activity) (Details) (SARs [Member], USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance	353,955
Exercised, Shares	(35,511)
Ending balance	318,444	353,955
Exercisable, Shares	264,976
Outstanding, Weighted Average Exercise Price	$ 35.52
Exercised, Weighted Average Exercise Price	$ 28.20
Outstanding, Weighted Average Exercise Price	$ 36.33	$ 35.52
Exercisable, Weighted Average Exercise Price	$ 33.34
Outstanding, Average Remaining Contractual Term Years	6 years 8 months 16 days	6 years 9 months 7 days
Outstanding, Average Remaining Contractual Term Years	6 years 8 months 16 days	6 years 9 months 7 days
Exercisable, Average Remaining Contractual Term Years	6 years 4 months 13 days
Outstanding, Aggregate Intrinsic Value	$ 6,277
Outstanding, Aggregate Intrinsic Value	6,307	6,277
Exercisable, Aggregate Intrinsic Value	$ 6,043