Time deposits (Details Textual) (USD $) In Millions, unless otherwise specified	1 Months Ended	2 Months Ended		12 Months Ended
	Dec. 31, 2011	Feb. 28, 2011	Dec. 31, 2012	Dec. 31, 2011 Time Deposit One [Member]	Dec. 31, 2011 Time Deposit Two [Member]	Dec. 31, 2011 Minimum [Member] Time Deposit One [Member]	Dec. 31, 2011 Minimum [Member] Time Deposit Two [Member]	Dec. 31, 2011 Maximum [Member] Time Deposit One [Member]	Dec. 31, 2011 Maximum [Member] Time Deposit Two [Member]
Time Deposits, $100,000 or More	$ 101.9		$ 81.2
Maturities of Time Deposits, Description				These time deposits had rates ranging from 0.50% to 2.00% and maturities ranging from March 2011 to January 2013.	These time deposits had rates ranging from 0.45% to 3.45% and maturities ranging from December 2011 to June 2014.
Accrued Liabilities	0.3
Proceeds From Internet Deposits		170
Time Deposit Interest Rate						0.50%	0.45%	2.00%	3.45%
Payments For Internet Deposits	$ 28