Commitments And Contingencies (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Commitments And Contingencies [Abstract]
Insurance balances receivable	$ 607,270	$ 529,927
Past due over 90 days	$ 3,668	$ 2,658
Percentage of premium receivables greater than 90 days past due	0.60%	0.50%

Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of all premiums and other types of receivables due from other persons or entities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.5)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_PremiumsAndOtherReceivablesNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant