Marketable Securities

12 Months Ended

Dec. 31, 2012

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Marketable Securities

Our marketable securities consist primarily of investments in preferred stock of $22.2 million and $20.9 million as of December 31, 2012 and 2011. We classify our marketable securities as available-for-sale and carry them at fair value with unrealized gains or losses classified as a component of accumulated other comprehensive income. Sales of marketable securities resulted in a realized gain of $0.0 million, $24.9 million and $0.3 million in for the years ended December 31, 2012, 2011 and 2010, respectively.

In January 2011, we sold our equity investment in DealerTrack Holdings, Inc., which was classified as available for sale with a carrying value of $51.3 million and a gross unrealized gain in other comprehensive income of $24.2 million, or $14.1 million net of tax, at December 31, 2010 for gross proceeds of $51.9 million and a realized pre-tax gain of $24.9 million.