ASC 230's indirect method requires every noncash component of net income to be reversed out to reach operating cash flow, but it leaves the level of detail to the company. The XBRL taxonomy offers OtherNoncashIncomeExpense for a net figure, and OtherNoncashExpense and OtherNoncashIncome for companies that show expense and income items separately. A noncash expense is added back; noncash income is subtracted.
Because the line is defined by what the company leaves out elsewhere, its contents vary widely. A small figure is typical. A large or fast-growing figure means something material is being grouped with minor items, and the notes or the MD&A liquidity discussion may be the only place it is explained. Some companies aggregate items that other filers break out, such as equity-method earnings or pension expense, so comparing this line across companies is rarely meaningful.
For analysis, the main question is whether the item will ever become cash. A noncash loss on remeasuring a liability may reverse later; an accrued legal settlement will eventually be paid. Analysts who treat operating cash flow as the cleaner measure of performance should check that it is not being supported by a large, unexplained "other" add-back. Tracking this line as a share of operating cash flow over several years is a quick way to spot that.