Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 15, 2019	Feb. 28, 2019	Dec. 31, 2018	Sep. 30, 2018	Aug. 14, 2018	Nov. 10, 2016	Nov. 04, 2015
Secured Debt | $108 Million Credit Facility
Maximum borrowing capacity	$ 108,000			$ 108,000	$ 108,000	$ 108,000
Secured Debt | $495 Million Credit Facility
Maximum borrowing capacity	495,000	$ 495,000	$ 495,000	495,000	495,000
Secured Debt | $400 Million Credit Facility
Maximum borrowing capacity	400,000			400,000	400,000		$ 400,000
Line of Credit Facility | $98 Million Credit Facility
Maximum borrowing capacity	$ 98,000			$ 98,000	$ 98,000			$ 98,000