Consolidated Statement of Shareholders' Equity (Parenthetical) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
Feb. 29, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statement of Shareholders' Equity
Dividends on common stock, per share (in dollars per share)	$ 0.09	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.18	$ 0.18	$ 0.18

Aggregate dividends declared 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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration