Stock-Based Compensation (Details Textual)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Stock Issued During Period, Shares, Restricted Stock Award, Gross	1,271,832	567,955	1,304,804	591,785
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	628,874	346,952	732,012	405,998
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	64,104	27,658	118,743	52,447
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	0	0	0	14,684
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	231,396	73,990	300,278	150,936