Securities Available for Sale and Held to Maturity (Tables)

12 Months Ended

Dec. 31, 2011

Securities Available for Sale and Held to Maturity [Abstract]

Amortized cost and estimated fair value of available for sale and held to maturity securities

The following table is a summary of the amortized cost and estimated fair value of securities available for sale and held to maturity at December 31, 2011 and 2010 ($ in thousands):

	Securities Available for Sale									Securities Held to Maturity
			Gross		Gross			Estimated				Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair		Amortized		Unrealized		Unrealized			Fair
December 31, 2011	Cost		Gains		(Losses)			Value		Cost		Gains		(Losses)			Value
U.S. Government agency obligations
Issued by U.S. Government agencies	$	3	$	-	$	-		$	3	$	-	$	-	$	-		$	-
Issued by U.S. Government sponsored agencies		64,573		229		-			64,802		-		-		-			-
Obligations of states and political subdivisions		190,868		11,971		(12	)		202,827		42,619		4,131		(2	)		46,748
Mortgage-backed securities
Residential mortgage pass-through securities
Guaranteed by GNMA		11,500		945		-			12,445		4,538		336		-			4,874
Issued by FNMA and FHLMC		340,839		7,093		-			347,932		588		28		-			616
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		1,570,782		44,183		-			1,614,965		7,749		133		(1	)		7,881
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		216,698		9,497		(176	)		226,019		2,211		185		-			2,396
Total	$	2,395,263	$	73,918	$	(188	)	$	2,468,993	$	57,705	$	4,813	$	(3	)	$	62,515
December 31, 2010
U.S. Government agency obligations
Issued by U.S. Government agencies	$	12	$	-	$	-		$	12	$	-	$	-	$	-		$	-
Issued by U.S. Government sponsored agencies		124,093		114		(2,184	)		122,023		-		-		-			-
Obligations of states and political subdivisions		159,418		2,259		(2,040	)		159,637		53,246		2,628		(10	)		55,864
Mortgage-backed securities
Residential mortgage pass-through securities
Guaranteed by GNMA		11,719		723		-			12,442		6,058		171		-			6,229
Issued by FNMA and FHLMC		432,162		1,188		(6,846	)		426,504		763		6		-			769
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		1,361,339		43,788		(4,311	)		1,400,816		78,526		1,503		-			80,029
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		54,331		2,007		(523	)		55,815		2,254		-		(2	)		2,252
Total	$	2,143,074	$	50,079	$	(15,904	)	$	2,177,249	$	140,847	$	4,308	$	(12	)	$	145,143

Securities with gross unrealized losses, segregated by length of impairment

The table below includes securities with gross unrealized losses segregated by length of impairment ($ in thousands)

	Less than 12 Months					12 Months or More					Total
			Gross					Gross					Gross
	Estimated		Unrealized			Estimated		Unrealized			Estimated		Unrealized
December 31, 2011	Fair Value		(Losses)			Fair Value		(Losses)			Fair Value		(Losses)
Obligations of states and political subdivisions	$	3,368	$	(12	)	$	202	$	(2	)	$	3,570	$	(14	)
Mortgage-backed securities
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		1,069		(1	)		-		-			1,069		(1	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		46,890		(176	)		-		-			46,890		(176	)
Total	$	51,327	$	(189	)	$	202	$	(2	)	$	51,529	$	(191	)
December 31, 2010
U.S. Government agency obligations
Issued by U.S. Government sponsored agencies	$	86,917	$	(2,184	)	$	-	$	-		$	86,917	$	(2,184	)
Obligations of states and political subdivisions		65,523		(2,045	)		307		(5	)		65,830		(2,050	)
Mortgage-backed securities
Residential mortgage pass-through securities
Issued by FNMA and FHLMC		312,787		(6,846	)		-		-			312,787		(6,846	)
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		232,279		(4,311	)		-		-			232,279		(4,311	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or GNMA		21,073		(525	)		-		-			21,073		(525	)
Total	$	718,579	$	(15,911	)	$	307	$	(5	)	$	718,886	$	(15,916	)

Gains and losses as a result of calls and disposition of securities

Gains and losses as a result of calls and disposition of securities were as follows ($ in thousands):

	Years Ended December 31,
Available for Sale	2011			2010		2009
Proceeds from calls and sales of securities	$	24,471		$	65,074	$	188,460
Gross realized gains		57			2,216		5,379
Gross realized (losses)		(11	)		-		(11	)
Held to Maturity
Proceeds from calls of securities	$	3,645		$	11,305	$	9,303
Gross realized gains		34			113		99

Contractual maturities of available for sale and held to maturity securities

Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Securities				Securities
	Available for Sale				Held to Maturity
			Estimated				Estimated
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
Due in one year or less	$	9,506	$	9,568	$	2,922	$	2,942
Due after one year through five years		59,092		61,549		18,377		19,922
Due after five years through ten years		176,050		185,097		19,824		22,298
Due after ten years		10,796		11,418		1,496		1,586
		255,444		267,632		42,619		46,748
Mortgage-backed securities		2,139,819		2,201,361		15,086		15,767
Total	$	2,395,263	$	2,468,993	$	57,705	$	62,515