Other expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Deposit liabilities investment expense (income)	$ 1,160	$ (1,838)	$ 1,472	$ (507)
Reinsurance contracts investment expense	2,686	2,224	7,292	6,861
Change in fair value of embedded derivatives in deposit and reinsurance contracts	0	(39)	88	(128)
Other expenses	$ 3,846	$ 347	$ 8,852	$ 6,226