Investment Securities (Tables)

12 Months Ended

Dec. 31, 2012

Investment Securities [Abstract]

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

	At December 31, 2012									At December 31, 2011
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Securities Held-to-Maturity
Corporate bonds:
Within 1 year	$	3,026	$	7	$	—		$	3,033	$	—	$	—	$	—		$	—
After 1 year to 5 years		66,819		1,526		(51	)		68,294		45,804		154		(319	)		45,639
		69,845		1,533		(51	)		71,327		45,804		154		(319	)		45,639
Total	$	69,845	$	1,533	$	(51	)	$	71,327	$	45,804	$	154	$	(319	)	$	45,639
Securities Available-for-Sale
U.S. treasuries:
Within 1 year	$	—	$	—	$	—		$	—	$	2,525	$	—	$	—		$	2,525
After 5 years to 10 years		4,960		—		(22	)		4,938		—		—		—			—
		4,960		—		(22	)		4,938		2,525		—		—			2,525
U.S. government corporations and agencies:
Within 1 year		1,517		9		—			1,526		10,009		77		—			10,086
After 1 year to 5 years		148,120		1,509		(70	)		149,559		143,189		1,022		(33	)		144,178
After 5 years to 10 years		20,953		109		(5	)		21,057		—		—		—			—
		170,590		1,627		(75	)		172,142		153,198		1,099		(33	)		154,264
State and political subdivisions:
Within 1 year		4,607		75		—			4,682		752		5		—			757
After 1 year to 5 years		4,130		88		(19	)		4,199		10,082		308		(16	)		10,374
After 5 years to 10 years		36,499		1,245		(7	)		37,737		11,846		664		(3	)		12,507
Over 10 years		70,495		5,055		—			75,550		87,896		5,472		(1	)		93,367
		115,731		6,463		(26	)		122,168		110,576		6,449		(20	)		117,005
Residential mortgage-backed securities:
After 5 years to 10 years		20,140		777		—			20,917		20,745		743		—			21,488
Over 10 years		66,962		2,861		—			69,823		55,328		2,665		(680	)		57,313
		87,102		3,638		—			90,740		76,073		3,408		(680	)		78,801
Commercial mortgage obligations:
After 1 year to 5 years		41		—		—			41		—		—		—			—
After 5 years to 10 years		626		7		—			633		5,547		124		—			5,671
Over 10 years		25,698		645		(5	)		26,338		54,994		799		—			55,793
		26,365		652		(5	)		27,012		60,541		923		—			61,464
Corporate bonds:
After 1 year to 5 years		4,993		21		—			5,014		4,991		—		(224	)		4,767
		4,993		21		—			5,014		4,991		—		(224	)		4,767
Money market mutual funds:
Within 1 year		4,878		—		—			4,878		3,851		—		—			3,851
		4,878		—		—			4,878		3,851		—		—			3,851
Equity securities:
No stated maturity		2,279		696		(133	)		2,842		2,364		544		(224	)		2,684
		2,279		696		(133	)		2,842		2,364		544		(224	)		2,684
Total	$	416,898	$	13,097	$	(261	)	$	429,734	$	414,119	$	12,423	$	(1,181	)	$	425,361

Information related to sales of securities available for sale

	Years Ended December 31,
(Dollars in thousands)	2012		2011		2010
Securities available for sale:
Proceeds from sales	$	57,186	$	40,481	$	13,466
Gross realized gains on sales		1,201		1,428		453
Gross realized losses on sales		896		11		21
Tax expense related to net realized gains on sales		107		496		151

Amount of securities in an unrealized loss position

	At December 31, 2012
	Less than  Twelve Months					Twelve Months  or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasuries	$	4,938	$	(22	)	$	—	$	—		$	4,938	$	(22	)
U.S. government corporations and agencies		36,793		(75	)		—		—			36,793		(75	)
State and political subdivisions		4,574		(14	)		480		(12	)		5,054		(26	)
Commercial mortgage obligations		5,006		(5	)		—		—			5,006		(5	)
Corporate bonds		10,410		(51	)		—		—			10,410		(51	)
Equity securities		976		(133	)		—		—			976		(133	)
Total	$	62,697	$	(300	)	$	480	$	(12	)	$	63,177	$	(312	)

	At December 31, 2011
	Less than Twelve Months					Twelve Months or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. government corporations and agencies	$	24,967	$	(33	)	$	—	$	—		$	24,967	$	(33	)
State and political subdivisions		—		—			1,997		(20	)		1,997		(20	)
Residential mortgage-backed securities		5,184		(20	)		3,311		(660	)		8,495		(680	)
Corporate bonds		34,851		(543	)		—		—			34,851		(543	)
Equity securities		920		(224	)		—		—			920		(224	)
Total	$	65,922	$	(820	)	$	5,308	$	(680	)	$	71,230	$	(1,500	)