Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Ceded premiums written	$ (92,503)	$ (103,517)	$ (273,514)	$ (290,836)
Ceded premiums earned	(89,156)	(92,884)	(271,874)	(274,947)
Ceded loss and loss expense incurred	(25,698)	(38,955)	(86,922)	(126,526)
National Flood Insurance Program [Member]
Ceded premiums written	(62,463)	(69,922)	(178,784)	(193,000)
Ceded premiums earned	(58,340)	(60,761)	(176,119)	(178,260)
Ceded loss and loss expense incurred	$ (15,382)	$ (14,008)	$ (36,315)	$ (48,099)
Percentage of NFIP claims ceded by federal government			100.00%