INVESTMENTS

The Company classifies the marketable securities in which it invests as available-for-sale securities. These securities are measured at fair market value in the financial statements with unrealized gains or losses recorded in Other comprehensive income in the Company's Consolidated Statements of Comprehensive Income. At the time the securities are sold or otherwise disposed of, gross realized gains and losses are included in Net income. Gross realized gains and losses are based on the carrying value (cost, net of discounts or premiums) of the sold investment. The amounts reclassified out of Other comprehensive income during the three-month periods ended March 31, 2015 and 2014, were insignificant. All of the marketable securities amounts are available to satisfy current obligations.

The amortized cost, gross unrealized gains, gross unrealized losses, and fair market value of available-for-sale investment securities by major security type and class of security at March 31, 2015, and December 31, 2014 are as follows:



		Investments
(In thousands)		Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair market value
2015
	Federal agency notes	$	168,485	$	97	$	—		$	168,582
	Commercial paper	110,130		2		(149		)	109,983
	Mutual funds	468		297		—			765
	Total	$	279,083	$	396	$	(149	)	$	279,330

2014
	Federal agency notes	$	143,132	$	40	$	(33	)	$	143,139
	Commercial paper	108,371		1		(257		)	108,115
	Mutual funds	344		279		—			623
	Total	$	251,847	$	320	$	(290	)	$	251,877

The mutual funds included in the investment table above are included in Other noncurrent assets on the Company's Consolidated Balance Sheets.

The maturities of available-for-sale securities at March 31, 2015 are as follows:



(In thousands)	Amortized cost		Fair market value
Federal agency notes
Due in one year or less	$	117,412	$	117,465
Due after one year through two years	51,073		51,117
Total	$	168,485	$	168,582

Commercial paper
Due in one year or less	$	77,447	$	77,365
Due after one year through two years	32,683		32,618
Total	$	110,130	$	109,983

The Company has long-term investments in several Canadian junior exploration companies, recorded on the Company's Consolidated Balance Sheets at cost. The Company determined that certain of its long-term investments were other than temporarily impaired and recorded a loss of less than $0.1 million for the quarter ended March 31, 2015. No adjustment was made to the carrying value of the Company's long-term investments for the quarter ended March 31, 2014. These long-term investments totaled less than $1.0 million for the periods ended March 31, 2015 and December 31, 2014, and are recorded in Other noncurrent assets on the Company's Consolidated Balance Sheets.