XML 23 R41.htm IDEA: XBRL DOCUMENT v3.20.1
Summary of Significant Accounting Policies - Additional Information (Detail)
3 Months Ended
Mar. 31, 2020
USD ($)
Countries
Dec. 31, 2019
USD ($)
Apr. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Joint venture capital contribution percentage     85.00%
Income accrual, description Income accrual is generally suspended for loans at the earlier of the date at which payments become 90 days past due or when, in the opinion of our Manager, recovery of income and principal becomes doubtful.    
Cash and cash equivalents, description Cash and cash equivalents represent cash held in banks and liquid investments with original maturities of three months or less.    
Borrower Escrows $ 459,100,000 $ 450,800,000  
Restricted cash $ 0 $ 0  
Number Of Countries | Countries 200    
Accounting Standards Update 2016-13 [Member]      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Cumulative-effect adjustment to retained earnings $ 17,700,000    
Walker and Dunlop [Member]      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Joint venture capital contribution percentage     15.00%