Summary of Business and Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of beginning of year	$ (9,042)
Amortization of prior service cost (credit)	776	$ 795
Net current period other comprehensive income	(5,269)	217
Balance as of end of year	(14,311)	(9,042)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of beginning of year	(9,042)	(9,259)
Other comprehensive (loss) income before reclassifications	(6,045)	(1,116)
Amortization of prior service cost (credit)	776	1,333
Net current period other comprehensive income	(5,269)	217
Balance as of end of year	$ (14,311)	$ (9,042)