American Idol Borrowing Cable Viewers?

Did American Idol hurt the cable news channels last night? FNC, CNN, and MSNBC have been heaping hours of coverage on the Fox reality hit — and Tuesday’s ratings suggest that viewers decided to watch Taylor and Katharine sing it out for #1.

At 8pm, the hour Idol aired on Fox, Bill O’Reilly was down about 20 percent from the day before (and his April average), and Paula Zahn averaged a measly 385,000, down more than 20 percent. (For some reason, Keith Olbermann didn’t move an inch.) By 9pm, Idol was over, but it was still a soft night for cable news. H&C averaged 1,127,000 viewers, compared to an average of 1,562,000 in April (and 1,666,000 the night before). Joe Scarborough — who has covered the Idol craze extensively — averaged 230,000, compared to 326,000 in April and 331,000 the night before. (He had just 58,000 in the demo.) Other ratings notes:

> At 10pm, Greta Van Susteren dipped below a million viewers for the first time since February with 973,000. (She had almost 1.5 million on Monday.) Anderson Cooper averaged 759,000 (up a bit from April averages).

> Remember yesterday’s post about Tim Russert‘s book tour? He appeared on H&C last night, and the program had FNC’s lowest demo of the night. He was on Larry King at the same time…