Bank subsidiary (Details 10) (USD $) In Thousands, unless otherwise specified	9 Months Ended				3 Months Ended	9 Months Ended				3 Months Ended	9 Months Ended				3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2011 years EGUs statements months contracts days institutions	Dec. 31, 2010	Sep. 30, 2011 Residential 1-4 family	Dec. 31, 2010 Residential 1-4 family	Sep. 30, 2011 Residential 1-4 family Troubled debt restructurings contracts	Sep. 30, 2011 Residential 1-4 family Troubled debt restructurings contracts	Dec. 31, 2010 Commercial real estate	Sep. 30, 2011 Residential land	Dec. 31, 2010 Residential land	Sep. 30, 2011 Residential land Troubled debt restructurings contracts	Sep. 30, 2011 Residential land Troubled debt restructurings contracts	Sep. 30, 2011 Residential land Troubled debt restructurings that subsequently defaulted contracts	Sep. 30, 2011 Commercial loans	Dec. 31, 2010 Commercial loans	Sep. 30, 2011 Commercial loans Troubled debt restructurings contracts	Sep. 30, 2011 Commercial loans Troubled debt restructurings contracts	Sep. 30, 2011 Commercial loans Troubled debt restructurings that subsequently defaulted contracts	Sep. 30, 2011 Commercial loans Troubled debt restructurings that subsequently defaulted contracts	Sep. 30, 2011 Troubled debt restructurings contracts	Sep. 30, 2011 Troubled debt restructurings contracts	Sep. 30, 2011 Troubled debt restructurings that subsequently defaulted contracts	Sep. 30, 2011 Troubled debt restructurings that subsequently defaulted contracts
Loan modifications determined to be troubled debt restructurings
Number of contracts					12	27				7	41	1			11	46	2	3	30	114	2	4
Pre-modification outstanding recorded investment					$ 3,255	$ 7,186				$ 2,366	$ 8,782				$ 5,433	$ 32,810			$ 11,054	$ 48,778
Post-modification outstanding recorded investment					2,922	6,371				2,358	8,772	528			5,433	32,810	631	797	10,713	47,953	631	1,325
Trouble debt restructured loans	$ 50,463	$ 38,837	$ 5,377	$ 5,150			$ 1,963	$ 25,028	$ 27,689				$ 20,058	$ 4,035
Period for which loan modifications are determined to be TDRs (in months)	12
Minimum period of payment default of loans determined to be TDRs (in days)	90
Number of loans modified by extending maturity date	3