Income Taxes - Textuals (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Change in Amount	$ 1,400,000	$ 286,000	$ 4,800,000
Valuation Allowance, Deferred Tax Asset, Change in Amount, Related to Property Impairment	2,000,000
Tax Basis of Investments, Unrealized Appreciation (Depreciation), Net	95,100,000	71,500,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	34.00%	34.00%	34.00%
Income Tax Expense (Benefit), Intraperiod Tax Allocation	2,705,000	(1,499,000)	(202,000)
Deferred Tax Assets, Inventory	4,000,000	5,100,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses	9,700,000	9,000,000
Deferred Tax Assets, Operating Loss Carryforwards	300,000	2,700,000
Deferred Tax Liabilities, Tax Deferred Income	2,000,000	1,700,000
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Income Tax Expense (Benefit), Intraperiod Tax Allocation	$ 600,000