Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Components of Income Tax Expense (Benefit) [Abstract]
Tax at statutory rate on earnings from continuing operations before unconsolidated entities, noncontrolling interest and income taxes	$ 25,248	$ 24,900	$ 21,199
State income taxes, net of federal benefit	3,431	3,383	2,881
Tax attributable to non-controlling interest	(70)	0	0
Tax at statutory rates on earnings not subject to federal and state income taxes	(28,572)	(28,283)	(24,080)
Other differences	100	96	82
Income tax expense	$ 137	$ 96	$ 82