Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Taxes
Effective tax rate (as a percent)	37.30%	2.30%	40.60%	2.30%
Discrete tax expense relating to a change in state apportionment (as a percent)			1.30%
Effective tax rate before discrete tax expense relating to a change in state apportionment (as a percent)			39.30%
Federal income tax			$ 0
State income tax			0
Unrecognized tax benefits, uncertain tax positions taken in prior years	973	18	973	18
Unrecognized tax benefits, interest and penalties accrued	$ 2		$ 11