Investments - Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 79,236	$ 80,463
Gross Unrealized Gains	109	56
Gross Unrealized Losses	(728)	(880)
Fair Value	78,617	79,639
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	595,120	463,143
Gross Unrealized Gains	2,533	2,079
Gross Unrealized Losses	(3,968)	(4,425)
Fair Value	593,685	460,797
Obligations of U.S. Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	104,979	107,312
Gross Unrealized Gains	262	348
Gross Unrealized Losses	(66)	0
Fair Value	105,175	107,660
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,113	36,486
Gross Unrealized Gains	762	630
Gross Unrealized Losses	(365)	(485)
Fair Value	34,510	36,631
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	431,030	319,345
Gross Unrealized Gains	1,508	1,101
Gross Unrealized Losses	(3,537)	(3,940)
Fair Value	429,001	316,506
US Treasury Bill Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,998
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Fair Value	24,999
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	14,741	14,759
Gross Unrealized Gains	33	11
Gross Unrealized Losses	(99)	(242)
Fair Value	14,675	14,528
Agency mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	64,495	65,704
Gross Unrealized Gains	76	45
Gross Unrealized Losses	(629)	(638)
Fair Value	$ 63,942	$ 65,111

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

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

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

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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