Investments - Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 42,514	$ 43,714
Gross Unrealized Gains	1,326	63
Gross Unrealized Losses	(3)	(336)
Fair Value	43,837	43,441
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	469,081	450,915
Gross Unrealized Gains	10,013	3,698
Gross Unrealized Losses	(580)	(2,843)
Fair Value	478,514	451,770
Obligations of U.S. Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	98,064	98,699
Gross Unrealized Gains	1,622	309
Gross Unrealized Losses	0	0
Fair Value	99,686	99,008
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	37,468	40,700
Gross Unrealized Gains	1,804	1,343
Gross Unrealized Losses	(307)	(342)
Fair Value	38,965	41,701
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	333,549	311,516
Gross Unrealized Gains	6,587	2,046
Gross Unrealized Losses	(273)	(2,501)
Fair Value	339,863	311,061
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	14,795	14,831
Gross Unrealized Gains	471	63
Gross Unrealized Losses	(3)	(50)
Fair Value	15,263	14,844
Agency mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	27,719	28,883
Gross Unrealized Gains	855	0
Gross Unrealized Losses	0	(286)
Fair Value	$ 28,574	$ 28,597