Real Estate Pro Forma Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended								8 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate [Line Items]
Total revenue	$ 82,605	$ 82,507	$ 85,023	$ 80,732	$ 81,746	$ 82,339	$ 77,106	$ 73,792	$ 12,650	$ 330,867	$ 314,983	$ 295,088
Operating Expenses									16,320	251,332	221,337	197,147
Operating income (loss)	22,091	27,275	17,249	12,920	23,792	26,477	20,048	23,329	(3,670)	79,535	93,646	97,941
Net income	$ 9,209	$ 14,271	$ 4,413	$ (691)	$ 9,731	$ 12,505	$ 7,588	$ 10,308	$ (3,670)	$ 27,202	40,132	45,637
Pro Forma
Real Estate [Line Items]
Total revenue											322,050	312,414
Operating Expenses											230,796	215,631
Operating income (loss)											91,255	96,783
Net income											$ 36,433	$ 41,916