Consolidated Statement of Shareholders' Equity Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Common Stock, Shares, Issued at Jan. 31, 2018	59,246,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 31, 2018	$ 2,921,492	$ 89	$ 827,301	$ (940,124)	$ 2,745,934	$ 288,292
Stock Issued During Period Value Benefit Plans and Exercise Of Equity Based Awards Net Of Tax	(5,814)	0	(12,771)	6,957	0	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	7,587	0	7,587	0	0	0
Other comprehensive income (loss), net of tax	(88,252)	0	0	0	0	(88,252)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	33,699	0	0	0	33,699	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2018	$ 2,868,712	89	822,117	(933,167)	2,779,633	200,040
Common Stock, Shares, Issued at Apr. 30, 2018	59,246,000
Common Stock, Shares, Issued at Jan. 31, 2019	59,246,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 31, 2019	$ 2,936,723	89	844,206	(1,037,872)	3,086,514	43,786
Treasury Stock, Value, Acquired, Cost Method	(35,681)	0	0	(35,681)	0	0
Stock Issued During Period Value Benefit Plans and Exercise Of Equity Based Awards Net Of Tax	(8,107)	0	(16,003)	7,896	0	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	8,305	0	8,305	0	0	0
Other comprehensive income (loss), net of tax	(40,734)	0	0	0	0	(40,734)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	55,400	0	0	0	55,400	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2019	$ 2,915,906	$ 89	$ 836,508	$ (1,065,657)	$ 3,141,914	$ 3,052
Common Stock, Shares, Issued at Apr. 30, 2019	59,246,000