Income Taxes Rollforward of Unrecognized Tax Benefits (Details) (Domestic Tax Authority [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits	$ 2,722	$ 0	$ 1,481	$ 0
Increases Related to Positions Taken During Prior Years	500	0
Increases Related to Positions Taken During the Current Year	741	0
Total Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2,722	$ 0