Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Interest	$ 1,964,000	$ 2,111,000
Federal income tax	0	0
National Flood Insurance Program [Member]
Restricted Cash	$ 33,500,000

- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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