Employee Benefit Plans (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock issued as stock awards	15,475	16,876
Incentive stock options and SARs exercisable period	10 years
Proceeds from exercise of stock options	$ 1,397,000	$ 488,000
Total intrinsic value of stock options exercised	200,000	100,000
Stock-based compensation expense	100,000	100,000
Unrecognized stock-based compensation expense	500,000
Weighted-average period, unrecognized expense expected to be recognized	1 year 9 months 18 days
Stock-based compensation expense related to restricted shares	100,000	100,000
Total expense associated with the retirement benefit plan	200,000	200,000
Contribution made by company	100,000	100,000
Non-Vested Restricted Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized stock-based compensation expense	$ 2,500,000
Weighted-average period, unrecognized expense expected to be recognized	4 years 4 months 24 days
Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock issued upon the exercise of stock options, SARs and stock awards	1,000,000
Common stock issued as stock awards	350,000