Bank segment - Contractual maturities of securities (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Amortized Cost
Due in one year or less	$ 0
Due after one year through five years	37,272
Due after five years through ten years	77,747
Due after ten years	53,124
Total amortized cost	168,143
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	525,014
Total available-for-sale securities, Amortized cost	693,157	$ 549,627
Fair value
Due in one year or less	0
Due after one year through five years	37,631
Due after five years through ten years	78,291
Due after ten years	52,537
Total fair value	168,459
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	525,061
Available-for-sale securities	$ 693,520	$ 550,394