Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Available-for-sale investments, at quoted market value, cost	$ 2,861	$ 2,741
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	9,207,874	9,062,633
Common stock, shares outstanding	9,207,874	9,062,633