Investments and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2012

Changes in Unrealized Gains and Losses on Available-for-sale Securities

Changes in unrealized gains and losses on available-for-sale securities are included in these financial statements as follows (in thousands):

	Year Ended December 31,
	2012		2011		2010
Changes in unrealized gains and losses on available-for- sale securities, net of tax, recorded in accumulated other comprehensive income (loss)	$	887	$	(385)	$	(406)

Aggregate Market Value and Unrealized Losses of Investment

The following table shows the number, aggregate market value and unrealized losses (in thousands) of investments with market values that were less than amortized cost as of December 31, 2012. These lower market values are primarily caused by fluctuations in credit spreads. Market values are expected to recover to the amortized cost prior to maturity.

	Unrealized Loss < 12 months					Unrealized Loss > 12 months
	Number of investments	Aggregate Market Value		Unrealized     Losses		Number of investments	Aggregate Market Value		Unrealized     Losses
Government securities	4	$	5,179	$	(3)	1	$	1,790	$	(0)
State and municipal bonds	19		24,969		(27)	1		1,092		(1)
Corporate Securities	33		15,429		(23)	14		7,262		(445)
Total	56	$	45,577	$	(53)	16	$	10,144	$	(446)

As of December 31, 2011, the number, aggregate market value and unrealized losses (in thousands) of investments with market values that were less than amortized cost were:

	Unrealized Loss < 12 months					Unrealized Loss > 12 months
	Number of investments	Aggregate Market Value		Unrealized Losses		Number of investments	Aggregate Market Value		Unrealized Losses
Government securities	5	$	4,599	$	(3)	6	$	6,708	$	(4)
State and municipal bonds	16		24,556		(7)	11		18,612		(36)
Corporate Securities	35		31,461		(855)	53		17,057		(532)
Total	56	$	60,616	$	(865)	70	$	42,377	$	(572)

Schedule of Realized Gains on the Sales of Available-For-Sale Securities

Using the specific identification method, the proceeds and realized gains on the sales of available-for-sale securities were as follows (in thousands):

	Year Ended December 31,
	2012			2011			2010
Proceeds	$	164,410		$	303,801		$	102,485
Realized gains		423			388			458
Realized losses		(78	)		(306	)		(198)
Net realized gains (losses) included in other comprehensive income (loss) as of the end of the prior year		285			159			(264)