COVID-19 Pandemic	3 Months Ended
	Mar. 31, 2021
Unusual or Infrequent Items, or Both [Abstract]
COVID-19 Pandemic	COVID-19 PANDEMICThe spread of COVID-19 and the resulting “shelter in place” and “stay at home” orders, travel restrictions and other precautions have caused significant disruptions in the United States economy, which could in turn disrupt the business, activities, and operations of Arrow’s customers, as well as Arrow's business and operations. The pandemic has also caused significant disruption in the financial markets both globally and in the United States. Arrow has taken steps to mitigate the risk of harm to its employees and customers and to its operations from the pandemic. In particular, Arrow, when necessary, has limited access to facilities to appointments only and encouraged customers to use contact-free alternatives like digital banking and ATMs. Arrow has also minimized contact for a large portion of its employee base through remote working, minimal travel and in-person meetings and social distancing.