Investment in Securities (Tables)

12 Months Ended

Dec. 31, 2012

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities [Table Text Block]

The table below presents the balances of securities available-for-sale measured at fair value on a recurring basis. The amortized cost, gross unrealized gains, gross unrealized losses and fair value of debt and equity securities are summarized as follows:

	December 31, 2012
			Gross		Gross
	Amortized		Unrealized		Unrealized
(In thousands)	Cost		Gains		Losses		Fair Value
State and political subdivisions	$	315,345	$	19,960	$	112	$	335,193
Certificates of deposit		6,742		—		—		6,742
Total	$	322,087	$	19,960	$	112	$	341,935
	December 31, 2011
			Gross		Gross
	Amortized		Unrealized		Unrealized
(In thousands)	Cost		Gains		Losses		Fair Value
State and political subdivisions	$	287,585	$	19,797	$	20	$	307,362
Certificates of deposit		3,250		—		—		3,250
Total	$	290,835	$	19,797	$	20	$	310,612

Schedule of Unrealized Loss on Investments [Table Text Block]

The fair values of securities with unrealized losses are as follows:

	December 31, 2012
	Less than 12 months				12 months or more				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
(In thousands)	Fair Value		Losses		Fair Value		Losses		Fair value		Losses
State and political subdivisions	$	19,758	$	112	$	—	$	—	$	19,758	$	112
Certificates of deposit		—		—		—		—		—		—
Total	$	19,758	$	112	$	—	$	—	$	19,758	$	112
	December 31, 2011
	Less than 12 months				12 months or more				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
(In thousands)	Fair Value		Losses		Fair Value		Losses		Fair value		Losses
State and political subdivisions	$	4,362	$	20	$	—	$	—	$	4,362	$	20
Certificates of deposit		—		—		—		—		—		—
Total	$	4,362	$	20	$	—	$	—	$	4,362	$	20

Schedule Of Amortized Cost And Fair Value [Table Text Block]

The amortized cost and fair value of debt and equity securities by contractual maturity are shown in the following table. Expected maturities may differ from contractual maturities because borrowers have the right to prepay obligations with or without prepayment penalties.

	December 31, 2012
(In thousands)	Amortized Cost		Fair Value
Due in 1 year or less	$	16,917	$	17,129
Due after 1 year through 5 years		63,064		67,493
Due after 5 years through 10 years		170,379		180,184
Due after 10 years		71,727		77,129
No stated maturity		—		—
Total	$	322,087	$	341,935