ISTANBUL — Turkey issued a blanket travel ban on all academics and opened top-to-bottom investigations into military courts Wednesday as security chiefs planned the next steps in sweeping crackdowns after last week’s failed coup.Already, the purges and probes have touched tens of thousands of people - judges, civil servants, military, police and others - as Turkey’s leaders seek to root out opponents and perceived internal dissident.The latest moves underscored the expanding reach of the fallout.At least 262 military judges and prosecutors were suspended as part of a full-scale investigation by the Defense Ministry into all personnel in its judiciary, the private NTV broadcaster reported without giving additional details.The travel restrictions on educators, reported the state broadcaster TRT, came after more than 15,000 education workers were suspended and resignations were demanded for all university deans.The government is presenting the measures as an effort to confront a wide-ranging conspiracy led by a U.S.-based Turkish cleric, and as a way of curbing the influence of the once-powerful military.