Revenue Recognition Revenue Recognition (Policies)	6 Months Ended
Revenue Recognition Revenue Recognition (Policies)	Jun. 30, 2018
Revenue Recognition [Abstract]
Revenue Recognition, Services, Management Fees [Policy Text Block]	Property Management provides on-site day-to-day real estate management services for owners of office, industrial, retail, multifamily residential and specialty properties, representing a series of daily performance obligations delivered over time. Pricing is generally in the form of a monthly management fee based upon property-level cash receipts, square footage under management or some other variable metric. Although we are principal in limited situations, we generally act as agent on behalf of our Property Management clients in relation to third-party vendors and subcontractors engaged to deliver operational services to our clients' properties. In these situations, we arrange but do not control the services provided by third-party vendors and subcontractors prior to the transfer of the services to the client. As a result, the costs incurred on behalf of clients, along with the corresponding revenue, are presented net on our Condensed Consolidated Statements of Comprehensive Income. Facilities Management primarily provides comprehensive, on-site day-to-day real estate management services to corporations and institutions across a broad range of industries that outsource the management of the real estate they occupy, representing a series of daily performance obligations delivered over time. Pricing generally includes a management fee and, in many instances, an incentive fee or other form of variable consideration. Although we may act as agent on behalf of our clients with respect to certain mandates, we generally act as principal for our Facilities Management contracts with respect to third-party vendors and subcontractors engaged to deliver operational services to our clients' facilities. In these situations, we control the services provided by such third-party vendors and subcontractors prior to the transfer of the services to the client. As a result, the costs incurred on behalf of our clients, along with the corresponding reimbursement revenue, are presented gross on our Condensed Consolidated Statements of Comprehensive Income.
Revenue Recognition, Real Estate Transactions, Policy [Policy Text Block]	Our performance obligation is to facilitate the execution of capital transactions and we are generally entitled to the full consideration at the point in time upon which our performance obligation is satisfied, at which time we recognize revenue.
Revenue Recognition, Leases [Policy Text Block]	Generally, we are either entitled to the full consideration upon lease execution or in part upon lease execution with the remainder upon the occurrence of a future event outside of our control (e.g. tenant occupancy, lease commencement, or rent commencement). The majority of the events that preclude our entitlement to the full consideration upon lease execution are considered to be “normal course of business” and, as a result, do not result in a constraint upon the recognition of revenue. In the infrequent instance our fee entitlement in a contract with a customer is predicated on the occurrence of future events that are uncertain of occurring, we constrain the recognition of revenue until the uncertainty is resolved or the future event occurs. Generally, less than 5% of our Leasing revenue recognized in the current period had previously been constrained.
Revenue Recognition, Milestone Method [Table Text Block]	Depending on the terms of our engagement, our performance obligation is either to arrange for the completion of a project or to assume responsibility for completing a project on behalf of a client. Our obligations to clients are satisfied over time due to the continuous transfer of control of the underlying asset. Therefore, we recognize revenue over time, primarily using input measures (e.g. to-date costs incurred relative to total estimated costs at completion). Typically, we are entitled to consideration at distinct milestones over the term of an engagement.
Advisory, Consulting and Other [Policy Text Block]	Advisory, Consulting and Other includes a variety of different service offerings, whereby our performance obligation is to provide services as specified in the contract. Occasionally, our entitlement to consideration is predicated on the occurrence of an event such as the delivery of a report for which client acceptance is required. However, except for event-driven point-in-time transactions, the majority of services provided within this service line are delivered over time due to the continuous transfer of control to our clients.
Management and Investment Advisory Fees, Policy [Policy Text Block]	LaSalle provides real estate investment management services to clients and earns consideration in the form of advisory fees, transaction fees, and incentive fees. Typically, our performance obligation is to manage clients’ capital for a specified period of time and is delivered as a series of daily performance obligations over time. Revenue recognition for transaction and incentive fees is generally constrained until all contingencies have cleared due to the possibility of a significant reversal until completion of the events necessary to realize the associated consideration. Substantially all incentive fees recognized as revenue were previously constrained.