Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	$ 904	$ 191,428
Less than 12 months, unrealized losses	5	2,062
12 months or more, fair value	23,051	30,415
12 months or more, unrealized losses	578	1,117
Total, fair value	23,955	221,843
Total, unrealized losses	583	3,179
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	0	2,199
Less than 12 months, unrealized losses	0	12
12 months or more, fair value	3,141	9,395
12 months or more, unrealized losses	310	380
Total, fair value	3,141	11,594
Total, unrealized losses	310	392
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	904	189,229
Less than 12 months, unrealized losses	5	2,050
12 months or more, fair value	19,910	21,020
12 months or more, unrealized losses	268	737
Total, fair value	20,814	210,249
Total, unrealized losses	$ 273	$ 2,787