Catastrophe Losses (Details) - Catastrophe [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) catastrophic_event	Dec. 31, 2014 USD ($) catastrophic_event	Dec. 31, 2013 USD ($) catastrophic_event
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	14	3	3
Catastrophic Event, Incurred Losses and Loss Adjustment Expense | $	$ 28,565	$ 829	$ 3,602
Catastrophic Events, Impact on Combined Ratio	8.50%	0.30%	1.80%
Catastrophe Loss Size, Range 3 [Member]
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	2
Catastrophic Event, Incurred Losses and Loss Adjustment Expense | $	$ 11,523
Catastrophic Events, Impact on Combined Ratio	3.40%
Catastrophe Loss Size, Range 1 [Member]
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	5	3	2
Catastrophic Event, Incurred Losses and Loss Adjustment Expense | $	$ 2,343	$ 829	$ 1,763
Catastrophic Events, Impact on Combined Ratio	0.70%	0.30%	0.90%
Catastrophe Loss Size, Range 2 [Member]
Liability for Catastrophe Claims [Line Items]
Number of Catastrophic Events | catastrophic_event	7		1
Catastrophic Event, Incurred Losses and Loss Adjustment Expense | $	$ 14,699		$ 1,839
Catastrophic Events, Impact on Combined Ratio	4.40%		0.90%