Amortized cost and estimated fair value of securities available-for-sale are summarized as follows: (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 701,956	$ 793,634
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	8,712	2,321
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	2,123	11,816
Available-for-sale Securities	708,545	784,139
US Government Agencies Debt Securities [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	171,585	260,150
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	941	228
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	706	4,033
Available-for-sale Securities	171,820	256,345
Residential Mortgage Backed Securities [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	434,042	477,949
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	5,404	1,575
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,417	7,293
Available-for-sale Securities	438,029	472,231
US States and Political Subdivisions Debt Securities [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	61,680	45,814
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	2,278	439
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		484
Available-for-sale Securities	63,958	45,769
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	9,532	9,503
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	82	79
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		6
Available-for-sale Securities	9,614	9,576
US Treasury and Government [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	24,919
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	7
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax
Available-for-sale Securities	24,926
Investment Securities [Member]
Marketable Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	198	218
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax
Available-for-sale Securities	$ 198	$ 218

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

No definition available.

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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