Borrowings Under Credit Facilities and Related Items (Tables)

6 Months Ended

Jun. 30, 2018

Line of Credit Facility [Abstract]

Aggregate borrowings under the unsecured line of credit arrangements

The following information relates to aggregate borrowings under the primary unsecured revolving credit facility for the periods presented (dollars in thousands): 

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017
Balance outstanding at quarter end(1)	$	540,000		$	385,000		$	540,000		$	385,000
Maximum amount outstanding at any month end	$	685,000		$	640,000		$	865,000		$	1,010,000
Average amount outstanding (total of daily
principal balances divided by days in period)	$	562,747		$	561,626		$	463,978		$	678,343
Weighted average interest rate (actual interest
expense divided by average borrowings outstanding)	3.04		%	1.94		%	2.91		%	1.87		%

⁽¹⁾ As of June 30, 2018, letters of credit in the aggregate amount of $22,365,000 have been issued, which reduces the borrowing capacity on the unsecured revolving credit facility.