Investments - Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 44,973	$ 45,985
Gross Unrealized Gains	0
Gross Unrealized Losses	(838)
Fair Value	44,135
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	402,389
Gross Unrealized Gains	5,019
Gross Unrealized Losses	(2,480)
Fair Value	404,928
Obligations of U.S. Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	99,330
Gross Unrealized Gains	769
Gross Unrealized Losses	0
Fair Value	100,099
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,274
Gross Unrealized Gains	1,093
Gross Unrealized Losses	(439)
Fair Value	32,928
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	270,785
Gross Unrealized Gains	3,157
Gross Unrealized Losses	(2,041)
Fair Value	271,901
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	14,866
Gross Unrealized Gains	0
Gross Unrealized Losses	(460)
Fair Value	14,406
Agency mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	30,107
Gross Unrealized Gains	0
Gross Unrealized Losses	(378)
Fair Value	$ 29,729