Marketable Securities - Summary of Marketable Securities Treated as Available-for-Sale Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities, Amortized cost	$ 27,065	$ 27,048	$ 26,048
Total available-for-sale securities, Gross unrealized gains	163	123	155
Total available-for-sale securities, Gross unrealized losses	0	(6)	0
Total available-for-sale securities, Fair value	27,228	27,165	26,203
Common stock
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities, Amortized cost	197	197	198
Total available-for-sale securities, Gross unrealized gains	163	123	97
Total available-for-sale securities, Gross unrealized losses	0	0	0
Total available-for-sale securities, Fair value	360	320	295
Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities, Amortized cost	26,868	26,851	25,850
Total available-for-sale securities, Gross unrealized gains	0	0	58
Total available-for-sale securities, Gross unrealized losses	0	(6)	0
Total available-for-sale securities, Fair value	$ 26,868	$ 26,845	$ 25,908

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details