Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	$ 74,670	$ 48,593
Less than 12 months, unrealized losses	(522)	409
12 months or more, fair value	24,701	127,255
12 months or more, unrealized losses	(866)	2,068
Total, fair value	99,371	175,848
Total, unrealized losses	(1,388)	2,477
Obligations of U.S. Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	0	5,399
Less than 12 months, unrealized losses	0	10
12 months or more, fair value	0	24,852
12 months or more, unrealized losses	0	143
Total, fair value	0	30,251
Total, unrealized losses	0	153
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	15,757	16,827
Less than 12 months, unrealized losses	(249)	343
12 months or more, fair value	3,563	5,349
12 months or more, unrealized losses	(343)	398
Total, fair value	19,320	22,176
Total, unrealized losses	(592)	741
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	58,913	26,367
Less than 12 months, unrealized losses	(273)	56
12 months or more, fair value	21,138	97,054
12 months or more, unrealized losses	(523)	1,527
Total, fair value	80,051	123,421
Total, unrealized losses	$ (796)	$ 1,583