Other Assets Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Abstract]
Goodwill, net	$ 313,180	$ 314,143	$ 331,884
Investments	45,244	41,287
Prepaid and other	35,595	17,937
Derivative assets	4,367	17,482
Furniture, fixtures, and equipment, net	6,590	6,127
Deferred financing costs, net	5,769	6,851
Total other assets	$ 410,745	$ 403,827