Investments - Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 77,641	$ 80,463
Gross Unrealized Gains	324	56
Gross Unrealized Losses	(134)	(880)
Fair Value	77,831	79,639
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	622,889	463,143
Gross Unrealized Gains	3,495	2,079
Gross Unrealized Losses	(2,527)	(4,425)
Fair Value	623,857	460,797
Obligations of U.S. Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	99,855	107,312
Gross Unrealized Gains	386	348
Gross Unrealized Losses	(6)	0
Fair Value	100,235	107,660
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,083	36,486
Gross Unrealized Gains	1,001	630
Gross Unrealized Losses	0	(485)
Fair Value	35,084	36,631
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	488,951	319,345
Gross Unrealized Gains	2,108	1,101
Gross Unrealized Losses	(2,521)	(3,940)
Fair Value	488,538	316,506
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	14,722	14,759
Gross Unrealized Gains	189	11
Gross Unrealized Losses	(7)	(242)
Fair Value	14,904	14,528
Agency mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	62,919	65,704
Gross Unrealized Gains	135	45
Gross Unrealized Losses	(127)	(638)
Fair Value	$ 62,927	$ 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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