How to thank a group of co-workers for their hospitality?


The company I work for has an office in Japan, and they've hosted me for a
couple of weeks. When that time comes to an end I'd like to thank them for
hosting me and making me feel welcomed. What would be an appropriate way to do
this?

お-疲れ-様 is one answer I've seen, but it I'm not sure: it seems to be used for
small things and I don't want to offend by giving the impression that I
thought their work was minor.

_edit:_ I saw that other question about thanking for hospitality but asked
anyway to ensure I found something appropriate for a business context. If that
question's answer is appropriate, then this question is a duplicate.




お疲れ様 is not appropriate for this case.  
If you're going to thank them by speech, the answers posted by Earthliŋ, the
links of which are shown by Earthliŋ in the comments, are appropriate.
However, I feel that it alone is not enough as the way of giving an address of
thanks for their hospitality for two weeks. But I think that elaborate speech
of gratitude similar to that of ordinary Japanese seems difficult for you.  
So, I recommend that you leave a gratitude letter in English for them, and you
say like
"皆{みな}さん、長｛なが｝い間｛あいだ｝大変｛たいへん｝お世話｛せわ｝なりました。どうもありがとうございました。日本語｛にほんご｝がへたなので英語｛えいご｝でお礼｛れい｝の手紙｛てがみ｝を書｛か｝きました。あとで読｛よ｝んでください。
_Thank you very much for your long-term support/hospitality. Because I am poor
in Japanese, I wrote a letter of thanks in English. Please read it later._ "
at the speech.

By the way, I think it is quite all right that you would read the draft in
Japanese at the speech.




お疲れ様 is not appropriate for this case.  
If you're going to thank them by speech, the answers posted by Earthliŋ, the
links of which are shown by Earthliŋ in the comments, are appropriate.
However, I feel that it alone is not enough as the way of giving an address of
thanks for their hospitality for two weeks. But I think that elaborate speech
of gratitude similar to that of ordinary Japanese seems difficult for you.  
So, I recommend that you leave a gratitude letter in English for them, and you
say like
"皆{みな}さん、長｛なが｝い間｛あいだ｝大変｛たいへん｝お世話｛せわ｝なりました。どうもありがとうございました。日本語｛にほんご｝がへたなので英語｛えいご｝でお礼｛れい｝の手紙｛てがみ｝を書｛か｝きました。あとで読｛よ｝んでください。
_Thank you very much for your long-term support/hospitality. Because I am poor
in Japanese, I wrote a letter of thanks in English. Please read it later._ "
at the speech.

By the way, I think it is quite all right that you would read the draft in
Japanese at the speech.

