diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index 12a2950..d3aaafb 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -1021,8 +1021,11 @@ def _afterpoint(string):
     2
     >>> _afterpoint("123,456.78")
     2
+    >>> _afterpoint("  123,456.78  ")
+    2
 
     """
+    string = string.strip()
     if _isnumber(string) or _isnumber_with_thousands_separator(string):
         if _isint(string):
             return -1
diff --git a/test/test_regression.py b/test/test_regression.py
index 9555676..4e5107c 100644
--- a/test/test_regression.py
+++ b/test/test_regression.py
@@ -211,6 +211,16 @@ def test_column_with_mixed_value_types():
     assert_equal(table, expected)
 
 
+def test_decimal_alignment_with_thousands_separator():
+    "Regression: decimal alignment must work for comma-grouped floats (issue #248)"
+    result = tabulate([[34454634.345], [3.0]], headers=["doesnt work"], floatfmt="17,.4f", tablefmt="simple")
+    rows = [row for row in result.splitlines() if "." in row and any(c.isdigit() for c in row)]
+    assert len(rows) == 2
+    # the decimal points of both rows must sit in the same column
+    dot_cols = {row.index(".") for row in rows}
+    assert len(dot_cols) == 1
+
+
 def test_latex_escape_special_chars():
     "Regression: escape special characters in LaTeX output (issue #32)"
     expected = "\n".join(