Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Effective Income Tax Rate Reconciliation [Line Items]
Tax expense at U.S. statutory rates									$ 10,486	$ 7,260	$ 8,875
State tax expense, net of federal benefit									1,356	1,116	1,523
Other, net									42	69	164
Change in valuation allowance on loss carry forwards									(34)	(15)	(162)
Income tax expense benefit									11,850	8,430	10,400
Discontinued operations									89	174	219
Total income tax provision	$ 3,489	$ 3,227	$ 3,438	$ 1,785	$ 2,674	$ 2,473	$ 2,251	$ 1,206	$ 11,939	$ 8,604	$ 10,619