Reinsurance - Schedule of Catastrophe Losses by Event Magnitude (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) catastrophic_event	Jun. 30, 2015 USD ($) catastrophic_event	Jun. 30, 2016 USD ($) catastrophic_event	Jun. 30, 2015 USD ($) catastrophic_event
Catastrophe
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	16	12	16	12
Catastrophic Event, Incurred Losses and Loss Adjustment Expense	$ 3,720	$ 6,517	$ 18,776	$ 21,777
Catastrophic Events, Impact on Combined Ratio	3.30%	8.10%	8.70%	13.70%
Catastrophe | Catastrophe Loss Size, Range 2 [Member]
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	4	7	9	7
Catastrophic Event, Incurred Losses and Loss Adjustment Expense	$ 5,688	$ 4,696	$ 14,789	$ 19,956
Catastrophic Events, Impact on Combined Ratio	5.00%	5.80%	6.90%	12.60%
Catastrophe | Catastrophe Loss Size, Range 1 [Member]
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	12	5	7	5
Catastrophic Event, Incurred Losses and Loss Adjustment Expense	$ (1,968)	$ 1,821	$ 3,987	$ 1,821
Catastrophic Events, Impact on Combined Ratio	(1.70%)	2.30%	1.80%	1.10%
Minimum | Catastrophe Loss Size, Range 3 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			$ 5,000	$ 5,000
Minimum | Catastrophe Loss Size, Range 2 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			1,000	1,000
Minimum | Catastrophe Loss Size, Range 1 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			0	0
Maximum | Catastrophe Loss Size, Range 3 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			10,000	10,000
Maximum | Catastrophe Loss Size, Range 2 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			5,000	5,000
Maximum | Catastrophe Loss Size, Range 1 [Member]
Liability for Catastrophe Claims [Line Items]
Catastrophic Event, Incurred Losses and Loss Adjustment Expense			$ 1,000	$ 1,000