Schedule III - Real Estate and Accumulated Depreciation - Reconciliation of Land, Buildings and Improvements, and Reconciliation of Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSET BASIS
Balance at beginning of period	$ 1,848,673	$ 1,683,803	$ 1,527,569
Additions to land, buildings and improvements	636,389	290,486	273,902
Disposition of land, buildings and improvements	(129,339)	(125,039)	(116,553)
Impairment loss	0	(577)	(1,115)
Balance at end of period	2,355,723	1,848,673	1,683,803
ACCUMULATED DEPRECIATION
Balance at beginning of period	241,760	212,207	179,455
Depreciation	85,524	72,063	63,675
Depreciation on assets sold or disposed	(37,218)	(42,510)	(30,923)
Balance at end of period	290,066	$ 241,760	$ 212,207
Aggregate cost of land, buildings, furniture and equipment for federal income tax purposes	$ 2,137,100
Hotel building and improvements | Minimum
ACCUMULATED DEPRECIATION
Useful lives	6 years
Hotel building and improvements | Maximum
ACCUMULATED DEPRECIATION
Useful lives	40 years
Furniture and equipment | Minimum
ACCUMULATED DEPRECIATION
Useful lives	2 years
Furniture and equipment | Maximum
ACCUMULATED DEPRECIATION
Useful lives	15 years