Investments (Tables)

12 Months Ended

Dec. 31, 2013

Investment in Marketable Securities [Abstract]

Investments

	At December 31, 2013
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Marketable securities	$	17,649	$	(3,300	)	$	172	$	14,521

	At December 31, 2012
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Marketable securities	$	34,786	$	(10,443	)	$	2,722	$	27,065

Gross unrealized losses on investment securities

The following table summarizes the gross unrealized losses on investment securities for which other-than-temporary impairments have not been recognized and the fair values of those securities, aggregated by the length of time the individual securities have been in a continuous unrealized loss position, at December 31, 2013 (in thousands):

	Less than twelve months					Twelve months or more				Total
	Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses			Fair Value
Marketable equity securities	$	(3,300	)	$	4,146	$	—	$	—	$	(3,300	)	$	4,146