Investment in Securities (Tables)

6 Months Ended

Jun. 30, 2019

Investments, Debt and Equity Securities [Abstract]

Schedule of Investment Securities

	June 30, 2019
			Gross		Gross
	Amortized		Unrealized		Unrealized
(In thousands)	Cost		Gains		Losses		Fair Value
State and political subdivisions	$	318,924	$	12,181	$	7	$	331,098
U.S. government agencies		102,091		554		347		102,298
Certificates of deposit		1,995		—		—		1,995
Total	$	423,010	$	12,735	$	354	$	435,391
	December 31, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized
(In thousands)	Cost		Gains		Losses		Fair Value
State and political subdivisions	$	332,732	$	3,791	$	1,806	$	334,717
U.S. government agencies		106,153		86		1,417		104,822
Certificates of deposit		1,995		—		—		1,995
Total	$	440,880	$	3,877	$	3,223	$	441,534

Schedule of the Fair Value of Securities with Unrealized Losses

	June 30, 2019
	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	$	1,007	$	—	$	2,976	$	7	$	3,983	$	7
U.S. government agencies		—		—		33,472		347		33,472		347
Total	$	1,007	$	—	$	36,448	$	354	$	37,455	$	354
	December 31, 2018
	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	$	91,248	$	556	$	60,546	$	1,250	$	151,794	$	1,806
U.S. government agencies		30,409		130		38,005		1,287		68,414		1,417
Total	$	121,657	$	686	$	98,551	$	2,537	$	220,208	$	3,223

Schedule of Amortized Cost and Fair Value of Investment

	June 30, 2019
(In thousands)	Amortized Cost		Fair Value
Due in 1 year or less	$	25,149	$	25,232
Due after 1 year through 5 years		114,928		116,965
Due after 5 years through 10 years		236,912		247,152
Due after 10 years		46,021		46,042
Total	$	423,010	$	435,391