Stockholders' Equity Dividend (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended			0 Months Ended
	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013	Feb. 26, 2015
Stockholders' Equity Attributable to Parent [Abstract]
Common Stock Dividend Per Share Annual Amount								$ 0.18
Dividends Payable [Line Items]
Dividends Payable, Date Declared	Nov. 20, 2014	Aug. 21, 2014	May 22, 2014	Feb. 27, 2014	Nov. 21, 2013	Aug. 22, 2013	May 23, 2013	Mar. 07, 2013
Dividends Payable, Date of Record	Dec. 10, 2014	Sep. 10, 2014	Jun. 10, 2014	Mar. 10, 2014	Dec. 10, 2013	Sep. 10, 2013	Jun. 10, 2013	Mar. 22, 2013
Dividends Payable, Date to be Paid	Jan. 02, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jan. 02, 2014	Sep. 30, 2013	Jul. 01, 2013	Apr. 10, 2013
Cash dividends declared per common share	$ 0.050	$ 0.050	$ 0.050	$ 0.050	$ 0.045	$ 0.045	$ 0.045	$ 0.045	$ 0.20	$ 0.18	$ 0
Payments of Dividends	$ 5,743	$ 5,697	$ 5,693	$ 5,778	$ 5,159	$ 5,096	$ 5,079	$ 5,064	$ 22,911	$ 20,398	$ 0
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared												Feb. 26, 2015
Dividends Payable, Date of Record												Mar. 10, 2015
Dividends Payable, Date to be Paid												Mar. 31, 2015
Cash dividends declared per common share												$ 0.055