Bank subsidiary (Details 4) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Amortized Cost
Due in one year or less	$ 10,800
Due after one year through five years	175,614
Due after five years through ten years	50,465
Due after ten years	9,066
Total amortized cost	245,945
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	308,901
Total available-for-sale securities, amortized cost	554,846	672,288
Fair value
Due in one year or less	10,814
Due after one year through five years	177,287
Due after five years through ten years	52,616
Due after ten years	9,475
Total fair value	250,192
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	320,853
Total available for sale securities	571,045	678,152
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(7)	(3,884)
Fair value, less than 12 months	13,886	277,781
Gross unrealized losses, total	(7)	(3,884)
Fair value, total	13,886	277,781
Federal agency obligations
Amortized Cost
Total available-for-sale securities, amortized cost	195,614	317,945
Fair value
Total available for sale securities	197,849	315,896
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months		(2,220)
Fair value, less than 12 months		205,316
Gross unrealized losses, total		(2,220)
Fair value, total		205,316
Mortgage-related securities - FNMA, FHLMC and GNMA
Amortized Cost
Total available-for-sale securities, amortized cost	308,901	310,711
Fair value
Total available for sale securities	320,852	319,970
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(6)	(311)
Fair value, less than 12 months	9,151	30,986
Gross unrealized losses, total	(6)	(311)
Fair value, total	9,151	30,986
Municipal bonds
Amortized Cost
Total available-for-sale securities, amortized cost	50,331	43,632
Fair value
Total available for sale securities	52,344	42,286
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(1)	(1,353)
Fair value, less than 12 months	4,735	41,479
Gross unrealized losses, total	(1)	(1,353)
Fair value, total	$ 4,735	$ 41,479