Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	$ 131,553	$ 48,593
Less than 12 months, unrealized losses	2,257	409
12 months or more, fair value	25,508	127,255
12 months or more, unrealized losses	1,061	2,068
Total, fair value	157,061	175,848
Total, unrealized losses	3,318	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	18,204	16,827
Less than 12 months, unrealized losses	574	343
12 months or more, fair value	4,234	5,349
12 months or more, unrealized losses	325	398
Total, fair value	22,438	22,176
Total, unrealized losses	899	741
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	113,349	26,367
Less than 12 months, unrealized losses	1,683	56
12 months or more, fair value	21,274	97,054
12 months or more, unrealized losses	736	1,527
Total, fair value	134,623	123,421
Total, unrealized losses	$ 2,419	$ 1,583