Quarterly report pursuant to Section 13 or 15(d)

Unsecured Line of Credit and Term Notes - Borrowings Outstanding on Unsecured Line of Credit and Term Notes (Detail)

v3.4.0.3
Unsecured Line of Credit and Term Notes - Borrowings Outstanding on Unsecured Line of Credit and Term Notes (Detail) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Unsecured Line Of Credit And Term Notes [Line Items]    
Revolving line of credit borrowings $ 141,000 $ 79,000
Total term notes payable 750,000 750,000
Term Note Due April 26, 2016 [Member]    
Unsecured Line Of Credit And Term Notes [Line Items]    
Total term notes payable 150,000 150,000
Term Note Due June 4, 2020 [Member]    
Unsecured Line Of Credit And Term Notes [Line Items]    
Total term notes payable 325,000 325,000
Term Note Due August 5, 2021 [Member]    
Unsecured Line Of Credit And Term Notes [Line Items]    
Total term notes payable 100,000 100,000
Term Note Due April 8, 2024 [Member]    
Unsecured Line Of Credit And Term Notes [Line Items]    
Total term notes payable $ 175,000 $ 175,000