XML 129 R55.htm IDEA: XBRL DOCUMENT v2.4.0.8
Subsequent Events - Additional Information (Detail) (USD $)
1 Months Ended 3 Months Ended 6 Months Ended 0 Months Ended
Apr. 30, 2013
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Jul. 16, 2013
Subsequent Event [Member]
Subsequent Event [Line Items]            
Dividends per common share $ 0.225 $ 0.23 $ 0.20 $ 0.45 $ 0.35 $ 0.225
Date of dividend payable           Sep. 20, 2013
Record date of dividend payable           Aug. 16, 2013