@parkbogerm: You can use the GET statuses/retweeters/ids endpoint.
$ twurl -H api.twitter.com "/1.1/statuses/retweeters/ids.json?id=914040437974867971"
{
"ids":[
800291790406369280,
361918251,
554332663,
759392452738371586,
1422632244,
4737081043,
825385114943107073,
1251933524,
2486554232,
879350944554565632,
889103066888261634,
956442145,
277300536,
346379422,
163920612,
824647321459716096,
2395699622,
76519304,
616912494,
150751035,
2822595307,
3080649372,
4583209274,
852556014352191488,
2951435635,
3232531682,
211788210,
3239859246,
873266118428733440,
829698047009497088,
4223645954,
2830601870,
1960820144,
3312630985,
232452413,
3866114052,
3505561645,
865207983520727040,
112710277,
887810509906432000,
821950806224011264,
203378280,
774296410850103296,
293495606,
3637030759,
766965400508567554,
701736979793182720,
544246209,
3513347532,
905442977971036160,
2839044307,
907251685306769408,
823535293819187201,
865480059825475584,
918110022294315009,
824519418382147584,
3285603661,
910508581971046400,
3136250172,
1306288333,
4461891912,
830716874358861824,
1095016536,
334736460,
755761181277556736,
911167817306611712,
4225271113,
124476359,
826724536448073728,
2571862832,
110385311,
3028096324,
720500431055622146,
749492233,
277821006,
538282404,
1295505889,
704864377824915456,
2491572332,
708210607,
2353044108,
185529030,
878880307788734464,
705722538928672769,
852165061426769920,
2242110504,
759008964591759360,
3313277035,
2978531030,
3151421545,
3194378389,
2273059838,
908294948989964288,
886789509949513728,
886387887922479105
],
"next_cursor":0,
"next_cursor_str":"0",
"previous_cursor":0,
"previous_cursor_str":"0"
}
However, note that the maximum number of user IDs returned is 100. If you need more than this, please see our Engagement API.