Quarterly Dividends Declared (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Oct. 31, 2014
Jul. 31, 2014
Apr. 30, 2014
Jan. 31, 2014
Dec. 31, 2012
Oct. 31, 2012
Aug. 31, 2012
Jul. 31, 2012
Apr. 30, 2012
Jan. 31, 2012
Dec. 31, 2014
Dec. 31, 2012
Dividend Declared [Line Items]                        
Approval Date 2014-10 2014-07 2014-04 2014-01 2012-12 2012-10 2012-08 2012-07 2012-04 2012-01   2012-12
Per share dividend $ 0.020 $ 0.020 $ 0.020 $ 0.020 $ 0.140 $ 0.035 $ 0.015 $ 0.020 $ 0.020 $ 0.020    
Date of record Nov. 07, 2014 Aug. 05, 2014 May 05, 2014 Feb. 07, 2014 Dec. 18, 2012 Nov. 02, 2012 Aug. 16, 2012 Aug. 03, 2012 May 04, 2014 Feb. 03, 2012    
Total amount $ 857 $ 856 $ 846 $ 771 $ 5,300 $ 1,300 $ 566 $ 755 $ 743 $ 751 $ 3,330 $ 9,376
Payment date Nov. 18, 2014 Aug. 15, 2014 May 15, 2014 Feb. 18, 2014 Dec. 31, 2012 Nov. 15, 2012 Aug. 31, 2012 Aug. 15, 2012 May 15, 2012 Feb. 15, 2012