Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Other Assets.
Deferred leasing costs	$ 30,943	$ 33,121
Deferred rent receivable	38,941	36,393
Internal-use software	16,171	14,440
Prepaid expense	8,252	4,390
Corporate furniture, fixtures and equipment	6,416	5,356
Deferred financing costs - revolving credit facility	1,281	1,604
Other	1,649	1,068
Total	$ 103,653	$ 96,372