Commitments, Off-Balance Sheet Arrangements and Contingent Liabilities (Details Textuals) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2011		Dec. 31, 2010		Dec. 31, 2008	Jun. 30, 2011 Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2010 Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2007 Indemnification Agreement [Member]	Jun. 30, 2011 Unfavorable litigation losses [Member]	Dec. 31, 2010 Unfavorable litigation losses [Member]
Loss Contingencies [Line Items]
Loss contingency reserve						$ 14,900,000	$ 17,400,000	$ 2,300,000	$ 1,500,000	$ 1,500,000
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Abstract]
Standby letters of credit Fair value	3,666,000	[1]	3,943,000	[1]
Carrying value of investments	41,000,000		45,000,000
Commitments under unconsolidated projects	11,000,000		11,000,000
Reduction in litigation reserve			300,000
Additional amount in the escrow amount			600,000
Remaining receivable in the escrow amount	1,500,000		1,300,000		2,000,000
Residential mortgage loans sold with recourse risk	47,000,000		58,000,000
Residential mortgage loans sold with credit recourse risk	561,000,000		667,000,000
Estimated fair value related to credit guarantee contracts	200,000		100,000
Reinsurance treaties minimum limit to assume liability for losses as percentage of aggregate risk exposure	5.00%
Reinsurance treaties maximum limit to assume liability for losses as percentage of aggregate risk exposure	10.00%
Corporations potential risk exposure	25,000,000
Corporations liability for reinsurance losses	$ 6,000,000		$ 4,500,000

[1] At June 30, 2011 and December 31, 2010, the commitment on standby letters of credit was $0.3 billion and $0.4 billion, respectively. See Note 12 for additional information on the standby letters of credit and for information on the fair value of lending-related commitments.