Stock Based Compensation (Additional Information Regarding Stock Award Activity) (Details) - Stock Awards [Member] - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average Grant Date Fair Value of Shares Granted During the Period (per share)		$ 17.59	$ 18.51	$ 17.59	$ 17.78
Total Grant Date Fair Value of Shares Vested During the Period		$ 3,727	$ 3,191	$ 4,073	$ 3,195
Share-based Liability Awards Paid During the Period	[1]	$ 0	$ 0	$ 0	$ 0

[1] Amount reflects the issuance of performance share awards during the period.