Note 5. Securities

The amortized cost and fair value of securities classified as available for sale follow (in thousands):


	December 31, 2011								December 31, 2010
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury	$	150	$	14	$	—		164	$	10,797	$	52	$	5		10,844
U.S. government agencies		248,595		1,308		—		249,903		106,054		971		434		106,591
Municipal obligations		294,489		15,218		42		309,665		181,747		4,107		5,411		180,443
Mortgage-backed securities		2,422,891		58,150		696		2,480,345		761,704		38,032		50		799,686
CMOs		1,426,495		21,774		2,193		1,446,076		367,662		6,880		2,491		372,051
Other debt securities		4,517		11		34		4,494		14,329		999		43		15,285
Other equity securities		4,208		2,086		41		6,253		3,428		660		103		3,985

	$	4,401,345	$	98,561	$	3,006	$	4,496,900	$	1,445,721	$	51,701	$	8,537	$	1,488,885

The following table presents the amortized cost and fair value of securities classified as available for sale at December 31, 2011, by contractual maturity (in thousands). Actual maturities will differ from contractual maturities because of rights to call or repay obligations with or without penalties.


	Amortized Cost		Fair Value
Due in one year or less	$	292,434	$	293,803
Due after one year through five years		915,985		934,279
Due after five years through ten years		405,288		421,935
Due after ten years		2,783,430		2,840,630
Equity securities		4,208		6,253

Total available for sale securities	$	4,401,345	$	4,496,900

The Company held no securities classified as held to maturity or trading at December 31, 2011 or 2010

The details concerning securities classified as available for sale with unrealized losses as of December 31, 2011 follow (in thousands):


	Losses < 12 months				Losses 12 months or >				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury	$	—	$	—	$	—	$	—	$	—	$	—
U.S. government agencies		—		—		—		—		—		—
Municipal obligations		18,854		42		—		—		18,854		42
Mortgage-backed securities		212,900		692		337		4		213,237		696
CMOs		296,860		2,193		—		—		296,860		2,193
Other debt securities		398		34		—		—		398		34
Equity securities		1,685		39		2		2		1,687		41

	$	530,697	$	3,000	$	339	$	6	$	531,036	$	3,006

The details concerning securities classified as available for sale with unrealized losses as of December 31, 2010 were as follows (in thousands):


	Losses < 12 months				Losses 12 months or >				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S Treasury	$	9,980	$	5	$	—	$	—	$	9,980	$	5
U.S. government agencies		74,566		434		—		—		74,566		434
Municipal obligations		57,713		3,092		19,870		2,319		77,583		5,411
Mortgage-backed securities		122		1		1,340		49		1,462		50
CMOs		122,312		2,491		—		—		122,312		2,491
Other debt securities		379		6		459		37		838		43
Equity securities		2,552		87		11		16		2,563		103

	$	267,624	$	6,116	$	21,680	$	2,421	$	289,304	$	8,537

Substantially all of the unrealized losses relate mainly to changes in market rates on fixed-rate debt securities since the respective purchase date. In all cases, the indicated impairment would be recovered by the security's maturity date or possibly earlier if the market price for the security increases with a reduction in the yield required by the market. None of the unrealized losses relate to the marketability of the securities or the issuer's ability to honor redemption of the obligations. The Company has adequate liquidity and, therefore, does not plan to sell and, is more likely than not, will not be required to sell these securities before recovery of the indicated impairment. Accordingly, the unrealized losses on these securities have been determined to be temporary.

Proceeds from sales of available for sale securities were approximately $342.9 million in 2011, $0.3 million in 2010 and $11.7 million in 2009. Realized gross gains and losses were insignificant. Substantially all of the proceeds in 2011 came from the sale of a portion of the portfolio acquired in the Whitney acquisition.

Securities with carrying values totaling approximately $3.0 billion at December 31, 2011 and $1.3 billion at December 31, 2010 were pledged primarily to secure public deposits or sold under agreements to repurchase.