Fair Value Measurements - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Total Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 7,996	$ 1,955	$ 4,083	$ 2,167
Total realized/unrealized gains (losses):
Included in other comprehensive income	(3,519)		0
Included in earnings and reported as net realized investment gains, net	3,579		3,579
Included in earnings and reported as losses incurred, net	0	0	0	0
Purchases	1,167	2,535	4,258	2,542
Sales	(4,125)	(247)	(6,822)	(466)
Balance at end of period	7,996	1,955	4,083	2,167	$ 5,098	$ 4,243
Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	1,056	1,634	1,228	1,846
Total realized/unrealized gains (losses):
Included in other comprehensive income	0		0
Included in earnings and reported as net realized investment gains, net	0		0
Included in earnings and reported as losses incurred, net	0	0	0	0
Purchases	0	0	0	7
Sales	(226)	(247)	(398)	(466)
Balance at end of period	1,056	1,634	1,228	1,846	830	1,387
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	6,940	321	2,855	321
Total realized/unrealized gains (losses):
Included in other comprehensive income	(3,519)		0
Included in earnings and reported as net realized investment gains, net	3,579		3,579
Included in earnings and reported as losses incurred, net	0	0	0	0
Purchases	1,167	2,535	4,258	2,535
Sales	(3,899)	0	(6,424)	0
Balance at end of period	6,940	321	2,855	321	4,268	2,856
Real Estate Acquired
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	9,642	7,995	12,149	12,658
Total realized/unrealized gains (losses):
Included in other comprehensive income	0		0
Included in earnings and reported as net realized investment gains, net	0		0
Included in earnings and reported as losses incurred, net	(501)	(1,031)	(143)	(1,503)
Purchases	8,938	9,632	27,953	26,346
Sales	(7,515)	(6,512)	(29,395)	(27,417)
Balance at end of period	$ 9,642	$ 7,995	$ 12,149	$ 12,658	$ 10,564	$ 10,084