Common Stock (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Class of Stock [Line Items]
Authorized shares to be repurchased	1,000,000								1,000,000
Shares previously purchased									42,600
Dividends declared (in dollars per share)	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.24	$ 0.24	$ 0.24
Subsequent Event
Class of Stock [Line Items]
Dividends declared (in dollars per share)	$ 0.07
Dividends paid (in dollars per share)									$ 0.07