Bank segment - Contractual maturities of securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 9,991
Due after one year through five years	81,303
Due after five years through ten years	81,439
Due after ten years	21,315
Total amortized cost	194,048
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	686,506
Total available-for-sale securities, Amortized cost	880,554	$ 823,756
Fair value
Due in one year or less	10,001
Due after one year through five years	83,162
Due after five years through ten years	83,406
Due after ten years	21,590
Total fair value	198,159
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	695,862
Available-for-sale securities	$ 894,021	$ 820,648