Note 8. Shareholders' Equity (Detail) - Potential Per Share Dividend Amounts (USD $)	Jun. 30, 2012
Quarterly [Member] | Thirty Dollars [Member]
Dividend payable per share	$ 0.01
Quarterly [Member] | Thirty Five Dollars [Member]
Dividend payable per share	$ 0.02
Quarterly [Member] | Forty Dollars [Member]
Dividend payable per share	$ 0.03
Quarterly [Member] | Forty Five Dollars [Member]
Dividend payable per share	$ 0.04
Quarterly [Member] | Fifty Dollars [Member]
Dividend payable per share	$ 0.05
Quarterly [Member] | Fifty Five Dollars [Member]
Dividend payable per share	$ 0.06
Quarterly [Member] | Sixty Dollars [Member]
Dividend payable per share	$ 0.07
Annual [Member] | Thirty Dollars [Member]
Dividend payable per share	$ 0.04
Annual [Member] | Thirty Five Dollars [Member]
Dividend payable per share	$ 0.08
Annual [Member] | Forty Dollars [Member]
Dividend payable per share	$ 0.12
Annual [Member] | Forty Five Dollars [Member]
Dividend payable per share	$ 0.16
Annual [Member] | Fifty Dollars [Member]
Dividend payable per share	$ 0.20
Annual [Member] | Fifty Five Dollars [Member]
Dividend payable per share	$ 0.24
Annual [Member] | Sixty Dollars [Member]
Dividend payable per share	$ 0.28