Consolidated Statements of Shareholders' Equity (unaudited) (Parenthetical) (USD $)	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Consolidated Statements of Shareholders' Equity (unaudited) [Abstract]
Cash dividends per share (in dollars per share)	$ 0.58	$ 0.54

Aggregate dividends paid during the period for each share of common stock outstanding.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	duration