Since you don't include your process or input data, may I simply suggest an alternative without Documents at all?
If your goal is to find entries in a specific column of an Excel file, you can do this in three operators: Read Excel, Aggregate and Filter Examples:
Use Read Excel to extract the column as an example set with a single attribute (e.g. words), Aggregate the words attribute with the count function and also group by words (this gives you your desired count per word) and finally use Filter Examples to only keep words with a count of 3 or more.
Example process (re-run the import configuration wizard for your specific setup):
<?xml version="1.0" encoding="UTF-8"?><process version="9.0.003">
<context>
<input/>
<output/>
<macros/>
</context>
<operator activated="true" class="process" compatibility="9.0.003" expanded="true" name="Process">
<process expanded="true">
<operator activated="true" class="read_excel" compatibility="9.0.003" expanded="true" height="68" name="Read Excel" width="90" x="45" y="34">
<parameter key="excel_file" value="D:\words.xlsx"/>
<parameter key="imported_cell_range" value="A1:A100"/>
<list key="annotations"/>
<parameter key="date_format" value="MMM d, yyyy h:mm:ss a z"/>
<list key="data_set_meta_data_information">
<parameter key="0" value="words.true.polynominal.attribute"/>
</list>
<parameter key="read_not_matching_values_as_missings" value="false"/>
</operator>
<operator activated="true" class="aggregate" compatibility="9.0.003" expanded="true" height="82" name="Aggregate" width="90" x="179" y="34">
<list key="aggregation_attributes">
<parameter key="words" value="count"/>
</list>
<parameter key="group_by_attributes" value="words"/>
</operator>
<operator activated="true" class="filter_examples" compatibility="9.0.003" expanded="true" height="103" name="Filter Examples" width="90" x="313" y="34">
<list key="filters_list">
<parameter key="filters_entry_key" value="count(words).ge.3"/>
</list>
</operator>
<connect from_op="Read Excel" from_port="output" to_op="Aggregate" to_port="example set input"/>
<connect from_op="Aggregate" from_port="example set output" to_op="Filter Examples" to_port="example set input"/>
<connect from_op="Filter Examples" from_port="example set output" to_port="result 1"/>
<portSpacing port="source_input 1" spacing="0"/>
<portSpacing port="sink_result 1" spacing="0"/>
<portSpacing port="sink_result 2" spacing="0"/>
<portSpacing port="sink_result 3" spacing="0"/>
</process>
</operator>
</process>