Commitments and Contingencies (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($) hotel_room	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) hotel_room extension_option	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)
Management Agreements [Line Items]
Combined base and incentive management fees	$ 6,000	$ 5,900	$ 17,400	$ 17,400
Commitments and Contingencies (Textual) [Abstract]
Reserve funds allowed for hotel maintenance from hotel revenue			4.00%
Restricted cash	$ 8,485		$ 8,485			$ 7,123
Total number of guest rooms | hotel_room	6,973		6,973
Ground rent expense	$ 3,600	$ 3,500	$ 10,100	$ 10,200
Hotel Zeppelin San Francisco [Member]
Commitments and Contingencies (Textual) [Abstract]
Number of guest rooms, leasehold interest | hotel_room			64
Total number of guest rooms | hotel_room	196		196
Monaco Washington DC [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2059
Base rent			$ 200
Argonaut Hotel [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2059
Base rent			$ 1,300
Hotel Zelos San Francisco [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2097
Hotel Zephyr Fisherman's Wharf [Member]
Commitments and Contingencies (Textual) [Abstract]
Base rent					$ 100
Hotel Zephyr Fisherman's Wharf [Member] | Primary lease [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2062
Ground lease percentage rent on hotel revenues					5.00%
Ground lease percentage rent on retail revenues					7.50%
Ground lease percentage rent on hotel revenues			6.00%
Ground lease percentage rent on retail and parking revenues			7.50%
Hotel Zeppelin San Francisco [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2059
Base rent			$ 500
Ground lease extension option			30 years
Number of extension options | extension_option			1
Hotel Palomar Los Angeles - Beverly Hills [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2107
Base rent			$ 3,800
Ground lease extension option			5 years
Number of extension options | extension_option			19
Union Station Hotel Nashville [Member]
Commitments and Contingencies (Textual) [Abstract]
Ground lease expiry period			2105
Base rent			$ 100
Minimum [Member]
Management Agreements [Line Items]
Terms of management agreements not including renewals			5 years
Terms of management agreements including renewals			5 years
Termination fees range			0
Base management fee from hotel revenues			2.00%
Minimum [Member] | Hotel Zelos San Francisco [Member]
Commitments and Contingencies (Textual) [Abstract]
Base rent increase			2.00%
Maximum [Member]
Management Agreements [Line Items]
Terms of management agreements not including renewals			21 years
Terms of management agreements including renewals			52 years
Termination fees range			4
Base management fee from hotel revenues			4.00%
Maximum [Member] | Hotel Zelos San Francisco [Member]
Commitments and Contingencies (Textual) [Abstract]
Base rent increase			4.00%