Bank subsidiary (Details 4) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Amortized Cost
Due in one year or less	$ 10,800
Due after one year through five years	272,346
Due after five years through ten years	41,577
Due after ten years	9,082
Total amortized cost	333,805
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	365,908
Total available-for-sale securities, amortized cost	699,713	672,288
Fair value
Due in one year or less	10,830
Due after one year through five years	273,366
Due after five years through ten years	41,673
Due after ten years	9,099
Total fair value	334,968
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	376,379
Total available for sale securities	711,347	678,152
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(554)	(3,884)
Fair value, less than 12 months	63,888	277,781
Gross unrealized losses, 12 months or more	(109)
Fair value, 12 months or more	20,164
Gross unrealized losses, total	(663)	(3,884)
Fair value, total	84,052	277,781
Federal agency obligations
Amortized Cost
Total available-for-sale securities, amortized cost	292,346	317,945
Fair value
Total available for sale securities	292,956	315,896
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(439)	(2,220)
Fair value, less than 12 months	39,555	205,316
Gross unrealized losses, total	(439)	(2,220)
Fair value, total	39,555	205,316
Mortgage-related securities - FNMA, FHLMC and GNMA
Amortized Cost
Total available-for-sale securities, amortized cost	365,908	310,711
Fair value
Total available for sale securities	376,379	319,970
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(100)	(311)
Fair value, less than 12 months	19,793	30,986
Gross unrealized losses, 12 months or more	(109)
Fair value, 12 months or more	20,164
Gross unrealized losses, total	(209)	(311)
Fair value, total	39,957	30,986
Municipal bonds
Amortized Cost
Total available-for-sale securities, amortized cost	41,459	43,632
Fair value
Total available for sale securities	42,012	42,286
Available-for-sale Securities, Continuous Unrealized Loss Position
Gross unrealized losses, less than 12 months	(15)	(1,353)
Fair value, less than 12 months	4,540	41,479
Gross unrealized losses, total	(15)	(1,353)
Fair value, total	$ 4,540	$ 41,479