Financing Receivables (Details 3) (Mortgage Loan Portfolio [Member], USD $) In Thousands, unless otherwise specified				6 Months Ended		12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2012 Additions [Member]	Jun. 30, 2012 Deductions [Member]	Dec. 31, 2011 Deductions [Member]
Schedule of activity of allowance for potential future losses on mortgage loans
Beginning of year	$ 2,517	$ 2,849	$ 3,410
Financing receivable, allowance for credit losses, period increase (decrease)				32	(364)	(561)
End of year	$ 2,517	$ 2,849	$ 3,410