IDT Financial Services Holding Limited Assets and Liabilities Held for Sale (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jul. 31, 2018
Current assets held for sale:
Cash and cash equivalents	$ 5,372	$ 5,892
Restricted cash and cash equivalents	158,881	128,931
Total current assets held for sale	167,083	137,272
Noncurrent assets held for sale:
Other assets	5,962	5,706
Current liabilities held for sale:
Total current liabilities held for sale	159,248	128,770
Noncurrent liabilities held for sale:
Total noncurrent liabilities held for sale	433	542
IDTFS Holding [Member]
Current assets held for sale:
Cash and cash equivalents	5,372	5,892
Restricted cash and cash equivalents	158,881	128,931
Trade accounts receivable, net of allowance for doubtful accounts of $1,715 and $2,192 at January 31, 2019 and July 31, 2018, respectively	2,110	1,265
Prepaid expenses	487	1,016
Other current assets	233	168
Total current assets held for sale	167,083	137,272
Noncurrent assets held for sale:
Property, plant and equipment, net	4	12
Other intangibles, net	176	190
Other assets	5,782	5,504
Total noncurrent assets held for sale	5,962	5,706
Current liabilities held for sale:
Trade accounts payable	631	776
Accrued expenses	279	407
Deferred revenue	58	12
Customer deposits	158,272	127,571
Other current liabilities	8	4
Total current liabilities held for sale	159,248	128,770
Noncurrent liabilities held for sale:
Other liabilities	433	542
Total noncurrent liabilities held for sale	$ 433	$ 542