Investment Securities Held-to-Maturity (Tables)

12 Months Ended

Dec. 31, 2012

Securities Available-for-Sale and Investment Securities Held-to-Maturity [Abstract]

Unrealized gain (losses) on securities

	December 31, 2012								December 31, 2011
			Gross		Gross		Estimated				Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	(dollars in thousands)
U.S. Government Sponsored Enterprise	$	17,747	$	19	$	8	$	17,758	$	26,979	$	36	$	2	$	27,013
U.S. Government Sponsored Enterprise Mortgage-Backed Securities		257,760		6,480		74		264,166		152,389		5,435		15		157,809
Total	$	275,507	$	6,499	$	82	$	281,924	$	179,368	$	5,471	$	17	$	184,822

Company's securities held-to-maturity

The following table shows the maturity distribution of the Company’s securities held-to-maturity at December 31, 2012.

	Amortized		Fair
	Cost		Value
	(dollars in thousands)
Within one year	$	6,780	$	6,865
After one but within five years		205,981		210,897
After five but within ten years		62,472		63,880
More than ten years		274		282
Total	$	275,507	$	281,924

Unrealized market loss of securities

In evaluating the underlying credit quality of a security, management considers several factors such as the credit quality of the obligor and the issuer, if applicable. Internal reviews of issuer financial statements are performed as deemed necessary.

	December 31, 2012
	Less Than 12 Months				12 Months or Longer				Total
			Unrealized				Unrealized				Unrealized
Temporarily Impaired Investments	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
	(dollars in thousands)
U.S. Government Sponsored Enterprises	$	9,994	$	8	$	—	$	—	$	9,994	$	8
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		8,936		50		5,371		24		14,307		74
Total temporarily impaired securities	$	18,930	$	58	$	5,371	$	24	$	24,301	$	82

The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at December 31, 2011.

	December 31, 2011
	Less Than 12 Months				12 Months or Longer				Total
			Unrealized				Unrealized				Unrealized
Temporarily Impaired Investments	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
	(dollars in thousands)
U.S. Government Sponsored Enterprises	$	4,994	$	2	$	—	$	—	$	4,994	$	2
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		5,367		15		—		—		5,367		15
Total temporarily impaired securities	$	10,361	$	17	$	—	$	—	$	10,361	$	17