Stockholders' Equity Dividend (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended								12 Months Ended
	Mar. 31, 2017	Mar. 10, 2017	Mar. 02, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Dividends Payable [Line Items]
Dividends Payable, Date Declared				Nov. 22, 2016	Aug. 18, 2016	May 19, 2016	Mar. 03, 2016	Nov. 19, 2015	Aug. 20, 2015	May 22, 2015	Feb. 26, 2015
Dividends Payable, Date of Record				Dec. 08, 2016	Sep. 19, 2016	Jun. 10, 2016	Mar. 10, 2016	Dec. 15, 2015	Sep. 10, 2015	Jun. 10, 2015	Mar. 10, 2015
Dividends Payable, Date to be Paid				Jan. 03, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jan. 04, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Cash dividends declared per common share				$ 0.055	$ 0.055	$ 0.055	$ 0.055	$ 0.055	$ 0.055	$ 0.055	$ 0.055	$ 0.22	$ 0.22	$ 0.20
Payments of Dividends				$ 6,026	$ 6,016	$ 5,886	$ 5,880	$ 6,326	$ 6,491	$ 6,389	$ 6,383	$ 23,808	$ 25,590	$ 22,911
Subsequent Event
Dividends Payable [Line Items]
Dividends Payable, Date Declared			Mar. 02, 2017
Dividends Payable, Date of Record		Mar. 14, 2017
Dividends Payable, Date to be Paid	Mar. 30, 2017
Cash dividends declared per common share			$ 0.055