Stockholders Equity (Share Repurchase Program) (Details) (USD $)	3 Months Ended	12 Months Ended	27 Months Ended
	Mar. 31, 2013	Dec. 31, 2011	Mar. 31, 2013
Equity [Abstract]
Stock repurchase program, authorized amount		$ 50,000,000
Stock repurchase program, shares acquired during period	89,485		164,559
Stock repurchase program, shares acquired during period, cost			$ 10,300,000
Stock repurchase program, shares acquired during period, weighted-average cost per share	$ 56.96