Other expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Income and Expenses [Abstract]
Deposit liabilities investment expense	$ 1,352	$ 512	$ 1,983	$ 1,043
Reinsurance contracts investment expense	1,533	325	3,303	438
Change in fair value of embedded derivatives in deposit and reinsurance contracts	(570)	183	(270)	326
Other expenses	$ 2,315	$ 1,020	$ 5,016	$ 1,807