Since your tax obligation "accrues" in 2017 but you will pay the tax in 2018, you may wish to review the "carryback" feature which might allow you to take credit in 2017 for tax paid in 2018.
See the instructions for Form 1116 at:
https://www.irs.gov/pub/irs-pdf/i1116.pdf
From Page 17:
"You can carry back 1 year and then
forward 10 years any foreign tax you
paid or accrued to any foreign country
or U.S. possession (reduced as
described under Line 12, later) on
income in a separate category that is
more than the limitation."
Also from Page 17:
"Generally, you can take a foreign tax
credit in the tax year you paid or
accrued the foreign taxes, depending
on your method of accounting. If you
report on the cash basis, you can
choose to take the credit for accrued
taxes by checking the “accrued” box in
Part II. But once you choose to do this,
you must credit foreign taxes in the year
they accrue on all future returns."
