Loans Payable (Details) (USD $)	1 Months Ended
	Feb. 28, 2011 Y	Aug. 31, 2009 Y	Mar. 31, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Revolving credit facility, term (years)	5
Revolving credit facility, maximum borrowing capacity	$ 100,000,000
Credit Agreement potential floating interest rate plus Federal Funds Rate	0.50%
Margin increase on Wells Fargo's prime rate			1.50%
Revolving credit facility, fees	500,000
Revolving credit facility, amount outstanding			71,000,000
Loan, principal amount outstanding		34,000,000
Loan, fixed interest rate		7.03%
Loan maturity period		5
Loan, amortization period (years)		25
Increase in interest rate due to default in repayment		5.00%
Loan, outstanding balance			104,142,000
Current portion of loans payable, Book Value			71,614,000	91,597,000
Long-term portion of loans payable, Book Value			32,528,000	32,133,000
Mutual Of Omaha Bank [Member]
Line of Credit Facility [Line Items]
Loan, outstanding balance			32,600,000
Current portion of loans payable, Book Value			600,000
Long-term portion of loans payable, Book Value			$ 32,000,000