XML 53 R8.htm IDEA: XBRL DOCUMENT v2.4.0.6
Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2012
Mar. 31, 2011
Mar. 31, 2010
Statement of Stockholders' Equity [Abstract]                      
Series B 6.75% convertible perpetual preferred stock, cash dividends declared per share $ 16.87 $ 16.88 $ 16.87 $ 16.88 $ 16.87 $ 16.88 $ 16.87 $ 16.88 $ 67.50 $ 67.50 $ 67.50
Common stock, cash dividends declared per share $ 0.49 $ 0.49 $ 0.48 $ 0.48 $ 0.48 $ 0.48 $ 0.47 $ 0.47 $ 1.94 $ 1.90 $ 1.86