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

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2011 4.00% Convertible Notes due in November, 2013	Dec. 31, 2010 4.00% Convertible Notes due in November, 2013	Dec. 31, 2012 5.375% Convertible Notes due in August, 2014	Dec. 31, 2011 5.375% Convertible Notes due in August, 2014	Dec. 31, 2010 5.375% Convertible Notes due in August, 2014	Jun. 30, 2009 5.375% Convertible Notes due in August, 2014
CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY
Cash dividends declared per share (in dollars per share)	$ 1.280
Long-term debt
Interest rate on debt (as a percent)		4.00%	4.00%	5.375%	5.375%	5.375%	5.375%