Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	$ 191,428	$ 48,593
Less than 12 months, unrealized losses	2,062	409
12 months or more, fair value	30,415	127,255
12 months or more, unrealized losses	1,117	2,068
Total, fair value	221,843	175,848
Total, unrealized losses	3,179	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	2,199	16,827
Less than 12 months, unrealized losses	12	343
12 months or more, fair value	9,395	5,349
12 months or more, unrealized losses	380	398
Total, fair value	11,594	22,176
Total, unrealized losses	392	741
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	189,229	26,367
Less than 12 months, unrealized losses	2,050	56
12 months or more, fair value	21,020	97,054
12 months or more, unrealized losses	737	1,527
Total, fair value	210,249	123,421
Total, unrealized losses	$ 2,787	$ 1,583