Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments [Abstract]

Aggregate Carrying And Approximate Market Values Of Available-For-Sale Securities

	December 31, 2017								December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Securities available-for-sale:
U.S. Treasuries and U.S.
government agencies	$	2	$	—	$	—	$	2	$	3	$	—	$	—	$	3
Obligations of states and
political subdivisions	94,552		2,051		407		96,196		83,248		594		1,474		82,368
Mortgage-backed securities:
U.S. government agencies	425,559		1,093		7,305		419,347		335,867		1,507		6,560		330,814
Private label	649		3		—		652		941		1		—		942
Trust preferred
securities	4,764		26		54		4,736		6,052		1,164		554		6,662
Corporate securities	21,916		475		123		22,268		23,925		127		478		23,574
Total Debt Securities	547,442		3,648		7,889		543,201		450,036		3,393		9,066		444,363
Marketable equity  securities	2,136		3,563		—		5,699		2,136		2,095		—		4,231
Investment funds	1,525		—		36		1,489		1,525		—		36		1,489
Total Securities
Available-for-Sale	$	551,103	$	7,211	$	7,925	$	550,389	$	453,697	$	5,488	$	9,102	$	450,083

Aggregate Carrying And Approximate Market Values Of Held-To-Maturity Securities

	December 31, 2017								December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Securities held-to-maturity:
U.S. government agencies	$	60,449	$	1,222	$	25	$	61,646	$	71,169	$	1,346	$	70	$	72,445
Trust preferred securities	4,000		—		—		4,000		4,000		—		—		4,000
Total Securities
Held-to-Maturity	$	64,449	$	1,222	$	25	$	65,646	$	75,169	$	1,346	$	70	$	76,445
Other investment securities:
Non-marketable equity securities	$	14,147	$	—	$	—	$	14,147	$	14,352	$	—	$	—	$	14,352
Total Other Investment
Securities	$	14,147	$	—	$	—	$	14,147	$	14,352	$	—	$	—	$	14,352

Gross Unrealized Losses And Fair Value Of Investments

The following table shows the gross unrealized losses and fair value of the Company’s investments aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):

	December 31, 2017
	Less Than Twelve Months				Twelve Months or Greater				Total
	Estimated Fair Value		Unrealized Loss		Estimated Fair Value		Unrealized Loss		Estimated Fair Value		Unrealized Loss
Securities available-for-sale:
Obligations of states and political subdivisions	$	4,913	$	28	$	19,440	$	379	$	24,353	$	407
Mortgage-backed securities:
U.S. Government agencies	172,807		1,887		140,226		5,418		313,033		7,305
Trust preferred securities	4,475		54		—		—		4,475		54
Corporate securities	3,357		49		2,350		74		5,707		123
Investment funds	1,500		36		—		—		1,500		36
Total	$	187,052	$	2,054	$	162,016	$	5,871	$	349,068	$	7,925

	December 31, 2016
	Less Than Twelve Months				Twelve Months or Greater				Total
	Estimated Fair Value		Unrealized Loss		Estimated Fair Value		Unrealized Loss		Estimated Fair Value		Unrealized Loss
Securities available-for-sale:
Obligations of states and political subdivisions	$	35,108	$	1,474	$	—	$	—	$	35,108	$	1,474
Mortgage-backed securities:
U.S. Government agencies	225,530		6,099		8,527		461		234,057		6,560
Trust preferred securities	—		—		4,971		554		4,971		554
Corporate securities	14,306		478		—		—		14,306		478
Investment funds	1,500		36		—		—		1,500		36
Total	$	276,444	$	8,087	$	13,498	$	1,015	$	289,942	$	9,102

Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity

The amortized cost and estimated fair value of debt securities at December 31, 2017, by contractual maturity, are shown in the following table (in thousands).  Expected maturities will differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties.  Mortgage-backed securities have been allocated to their respective maturity groupings based on their contractual maturity.

	Cost		Estimated Fair Value
Securities Available-for-Sale
Due in one year or less	$	3,002	$	3,005
Due after one year through five years	15,824		15,854
Due after five years through ten years	76,555		75,450
Due after ten years	452,061		448,892
	$	547,442	$	543,201
Securities Held-to-Maturity
Due in one year or less	$	—	$	—
Due after one year through five years	—		—
Due after five years through ten years	—		—
Due after ten years	64,449		65,646
	$	64,449	$	65,646

Gross Gains And Losses Realized

Gross gains and gross losses realized by the Company from investment security transactions are summarized in the table below (in thousands):

	For the year ended December 31,
	2017		2016			2015
Gross realized gains	$	4,476	$	3,978		$	2,142
Gross realized losses	—		(465		)	(12		)
Investment security gains (losses)	$	4,476	$	3,513		$	2,130