Deferred Policy Acquisition Costs Components of Deferred Acquisition Costs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Deferred Acquisition Costs [Line Items]
Beginning balance, net	$ (1,417)	$ 287
Additions	9,172	6,209
Amortization	(10,589)	(5,922)
Balance at March 31, net	$ 12,685	$ 8,403	$ 14,102	$ 8,116