Bank subsidiary (Details 6) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Amortized Cost
Due in one year or less	$ 0
Due after one year through five years	34,456
Due after five years through ten years	32,321
Due after ten years	21,139
Total amortized cost	87,916
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	434,364
Total available-for-sale securities, Amortized cost	522,280	535,090
Fair value
Due in one year or less	0
Due after one year through five years	34,446
Due after five years through ten years	32,370
Due after ten years	19,704
Total fair value	86,520
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	431,014
Available-for-sale securities	$ 517,534	$ 529,007