Fair Value (Details 1) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Fair value measurement using significant unobservable input
Securities available-for-sale	$ 835,424	$ 835,424	$ 853,725
Reconciliation and income statement classification of gains and losses for all assets measured at fair value on a recurring basis using significant unobservable inputs
Beginning balance	15,963	16,578	19,600
Total realized/unrealized gains or losses - Included in earnings	0	0	0
Total realized/unrealized gains or losses - Included in other comprehensive income	1,547	1,690	(2,066)
Transfers	0	0
Purchases			0
Settlements	(138)	(896)	(956)
Ending balance	17,372	17,372	16,578
US Government Agencies Debt Securities [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	14,534	14,534	13,249
State and Municipal Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	231,252	231,252	218,923
Reconciliation and income statement classification of gains and losses for all assets measured at fair value on a recurring basis using significant unobservable inputs
Beginning balance	3,680	4,210	4,725
Total realized/unrealized gains or losses - Included in earnings	0	0	0
Total realized/unrealized gains or losses - Included in other comprehensive income	0	0	0
Transfers	0	0
Purchases			0
Settlements	0	(530)	(515)
Ending balance	3,680	3,680	4,210
Collateralized Debt Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	13,692	13,692	12,368
Reconciliation and income statement classification of gains and losses for all assets measured at fair value on a recurring basis using significant unobservable inputs
Beginning balance	12,283	12,368	14,875
Total realized/unrealized gains or losses - Included in earnings	0	0	0
Total realized/unrealized gains or losses - Included in other comprehensive income	1,547	1,690	(2,066)
Transfers	0	0
Purchases			0
Settlements	(138)	(366)	(441)
Ending balance	13,692	13,692	12,368
Mortgage Backed Securities - Residential
Fair value measurement using significant unobservable input
Securities available-for-sale	228,340	228,340	261,005
Mortgage Backed Securities - Commercial
Fair value measurement using significant unobservable input
Securities available-for-sale	1	1	4
Collateralized Mortgage Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	347,605	347,605	348,176
Fair Value, Inputs, Level 3 [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	17,372	17,372	16,578
Fair Value, Inputs, Level 3 [Member] \| US Government Agencies Debt Securities [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 3 [Member] \| State and Municipal Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	3,680	3,680	4,210
Fair Value, Inputs, Level 3 [Member] \| Collateralized Debt Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	13,692	13,692	12,368
Fair Value, Inputs, Level 3 [Member] \| Mortgage Backed Securities - Residential
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Mortgage Backed Securities - Commercial
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| US Government Agencies Debt Securities [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| State and Municipal Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| Collateralized Debt Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| Mortgage Backed Securities - Residential
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| Mortgage Backed Securities - Commercial
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 2 [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	818,052	818,052	837,147
Reconciliation and income statement classification of gains and losses for all assets measured at fair value on a recurring basis using significant unobservable inputs
Derivative Assets	484	484	653
Derivative Liability	484	484	653
Fair Value, Inputs, Level 2 [Member] \| US Government Agencies Debt Securities [Member]
Fair value measurement using significant unobservable input
Securities available-for-sale	14,534	14,534	13,249
Fair Value, Inputs, Level 2 [Member] \| State and Municipal Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	227,572	227,572	214,713
Fair Value, Inputs, Level 2 [Member] \| Collateralized Debt Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	0	0	0
Fair Value, Inputs, Level 2 [Member] \| Mortgage Backed Securities - Residential
Fair value measurement using significant unobservable input
Securities available-for-sale	228,340	228,340	261,005
Fair Value, Inputs, Level 2 [Member] \| Mortgage Backed Securities - Commercial
Fair value measurement using significant unobservable input
Securities available-for-sale	1	1	4
Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Obligations
Fair value measurement using significant unobservable input
Securities available-for-sale	$ 347,605	$ 347,605	$ 348,176

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

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