DEBT - Summary of outstanding indebtedness (Details)									12 Months Ended
	Dec. 28, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 24, 2015 USD ($) Property Loan	Dec. 19, 2014 USD ($) contract	May 06, 2014 USD ($)	Mar. 28, 2014 Loan	Jan. 10, 2014 USD ($) Room	Jul. 26, 2013 USD ($)	Dec. 31, 2017 USD ($) Room Property	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) Room	Jan. 15, 2016 USD ($)	Jul. 22, 2013 USD ($) Property	Mar. 08, 2013 USD ($) Property	Mar. 07, 2013 USD ($) Property	Jan. 25, 2013 USD ($) Property
Debt Instrument [Line Items]
Debt outstanding									$ 873,109,000		$ 657,550,000
Unamortized debt issuance costs									(4,873,000)		(5,136,000)
Debt, net of issuance costs									$ 868,236,000		$ 652,414,000
Number of guestrooms | Room									2,442		749
Unsecured debt | Senior unsecured credit facility $450 Million
Debt Instrument [Line Items]
Debt outstanding									$ 165,000,000		$ 200,000,000
Loan amount									450,000,000.0		450,000,000
Unsecured debt | $150 Million Term Loan
Debt Instrument [Line Items]
Debt outstanding									$ 150,000,000		150,000,000
Stated interest rate									3.40%
Loan amount												$ 150,000,000.0
Unsecured debt | KeyBank National Association Term Loan due April 7, 2022
Debt Instrument [Line Items]
Debt outstanding									$ 140,000,000		140,000,000
Stated interest rate									3.51%
Unsecured debt | Keybank National Association Term Loan due November 25, 2022
Debt Instrument [Line Items]
Debt outstanding									$ 225,000,000		0
Stated interest rate									3.11%
Unsecured debt | Revolving credit facility | $300 Million Revolver
Debt Instrument [Line Items]
Debt outstanding									$ 15,000,000		50,000,000
Stated interest rate									3.21%
Mortgage loans
Debt Instrument [Line Items]
Debt outstanding									$ 343,109,000		317,550,000
Number of properties encumbered | Property									33
Mortgage loans | Voya (formerly known as ING Life Insurance and Annuity) term loans
Debt Instrument [Line Items]
Stated interest rate			5.18%
Number of properties encumbered | Property			9
Number of loans | Loan			4
Loan amount			$ 115,400,000
Mortgage loans | Voya (formerly known as ING Life Insurance and Annuity) 5.18% Fixed due March 1, 2019 One
Debt Instrument [Line Items]
Debt outstanding									$ 40,015,000		41,328,000
Stated interest rate									5.18%
Number of properties encumbered | Property									2
Amortization Period (Years)									20 years
Mortgage loans | Voya (formerly known as ING Life Insurance and Annuity) 5.18% Fixed due March 1, 2019 Two
Debt Instrument [Line Items]
Debt outstanding									$ 35,865,000		37,042,000
Stated interest rate									5.18%
Number of properties encumbered | Property									4
Amortization Period (Years)									20 years
Mortgage loans | Voya (formerly known as ING Life Insurance and Annuity) 5.18% Fixed due March 1, 2019 Three
Debt Instrument [Line Items]
Debt outstanding									$ 23,130,000		23,889,000
Stated interest rate									5.18%
Number of properties encumbered | Property									2
Amortization Period (Years)									20 years
Mortgage loans | Voya (formerly known as ING Life Insurance and Annuity) 5.18% Fixed due March 1, 2019 Four
Debt Instrument [Line Items]
Debt outstanding									$ 16,431,000		16,970,000
Stated interest rate									5.18%
Number of properties encumbered | Property									1
Amortization Period (Years)									20 years
Mortgage loans | KeyBank National Association 4.46% Fixed due February 1, 2023
Debt Instrument [Line Items]
Debt outstanding									$ 26,928,000		27,473,000
Stated interest rate									4.46%							4.46%
Number of properties encumbered | Property									4							4
Amortization Period (Years)									30 years
Loan amount																$ 29,400,000
Mortgage loans | KeyBank National Association 4.52% Fixed due April 1, 2023
Debt Instrument [Line Items]
Debt outstanding									$ 20,877,000		21,291,000
Stated interest rate									4.52%
Number of properties encumbered | Property									3						3
Amortization Period (Years)									30 years
Loan amount															$ 22,700,000
Mortgage loans | KeyBank National Association 4.30% Fixed due April 1, 2023
Debt Instrument [Line Items]
Debt outstanding									$ 20,211,000		20,626,000
Stated interest rate									4.30%					4.30%
Number of properties encumbered | Property									3					3
Amortization Period (Years)									30 years
Loan amount														$ 22,000,000
Mortgage loans | KeyBank National Association 4.95% Fixed due August 1, 2023
Debt Instrument [Line Items]
Debt outstanding									$ 36,093,000		36,741,000
Stated interest rate									4.95%				4.95%
Number of properties encumbered | Property									2				2
Amortization Period (Years)									30 years
Loan amount													$ 38,700,000
Mortgage loans | Bank of America Commercial Mortgage 6.41% Fixed due September 1, 2017
Debt Instrument [Line Items]
Debt outstanding									$ 0		7,661,000
Stated interest rate									6.41%
Number of properties encumbered | Property									0
Amortization Period (Years)									25 years
Prepayment penalties									$ 0
Mortgage loans | West Alliance Bank (formerly GE Capital Financial Inc.) 5.39% Fixed due April 1, 2020 one
Debt Instrument [Line Items]
Debt outstanding									$ 8,701,000		8,912,000
Stated interest rate						5.39%			5.39%
Number of properties encumbered | Property									1
Amortization Period (Years)									25 years
Mortgage loans | West Alliance Bank (formerly GE Capital Financial Inc.) 5.39% Fixed due April 1, 2020 two
Debt Instrument [Line Items]
Debt outstanding									$ 4,685,000		4,798,000
Stated interest rate									5.39%
Number of properties encumbered | Property									1
Amortization Period (Years)									25 years
Mortgage loans | MetaBank 4.25% Fixed due August 1, 2018
Debt Instrument [Line Items]
Debt outstanding									$ 0		6,588,000
Stated interest rate								4.25%	4.25%
Number of properties encumbered | Property									0
Amortization Period (Years)									20 years
Loan amount								$ 7,400,000
Prepayment penalties									$ 100,000
Mortgage loans | Meta Bank 4.44% Fixed due July 1, 2027
Debt Instrument [Line Items]
Debt outstanding									$ 47,640,000		0
Stated interest rate									4.44%
Number of properties encumbered | Property									3
Amortization Period (Years)									25 years
Mortgage loans | Bank of Cascades loan(s)
Debt Instrument [Line Items]
Number of loans | contract				2
Amortization Period (Years)				25 years
Loan increase				$ 7,900,000
Mortgage loans | Bank Of Cascades Variable due December 19, 2024, Note A
Debt Instrument [Line Items]
Debt outstanding									$ 9,023,000		9,289,000
Stated interest rate									3.56%
Number of properties encumbered | Property									1
Amortization Period (Years)									25 years
Mortgage loans | Bank Of Cascades 4.30% Fixed due December 19, 2024, Note B
Debt Instrument [Line Items]
Debt outstanding									$ 9,023,000		9,289,000
Stated interest rate				4.30%					4.30%
Number of properties encumbered | Property									0
Amortization Period (Years)									25 years
Mortgage loans | Compass Bank 3.17% Variable due May 6, 2020
Debt Instrument [Line Items]
Debt outstanding									$ 22,773,000		23,394,000
Stated interest rate									3.96%
Number of properties encumbered | Property									3
Amortization Period (Years)					25 years				25 years
Loan amount					$ 25,000,000
Mortgage loans | Mortgage Loans with General Electric Capital Corporation
Debt Instrument [Line Items]
Number of loans | Loan						2
Mortgage loans | West Alliance Bank (formerly GE Capital Corp) 5.39% Fixed due April 1, 2020, one
Debt Instrument [Line Items]
Debt outstanding									$ 5,769,000		5,910,000
Stated interest rate						5.39%			5.39%
Number of properties encumbered | Property									1
Amortization Period (Years)									25 years
Mortgage loans | West Alliance Bank (formerly GE Capital Corp) 5.39% Fixed due April 1, 2020, two
Debt Instrument [Line Items]
Debt outstanding									$ 4,926,000		5,046,000
Stated interest rate									5.39%
Number of properties encumbered | Property									1
Amortization Period (Years)									25 years
Mortgage loans | U.S. Bank, NA 6.13% Fixed due November 11, 2021
Debt Instrument [Line Items]
Debt outstanding									$ 11,019,000		$ 11,303,000
Stated interest rate							6.133%		6.13%
Number of properties encumbered | Property									1
Amortization Period (Years)							25 years		25 years
Prepayment penalty period until July 26, 2015 | Mortgage loans | MetaBank 4.25% Fixed due August 1, 2018
Debt Instrument [Line Items]
Prepayment penalties (as a percent)								3.00%
Prepayment penalty period after July 26, 2015 until July 26 2017 | Mortgage loans | MetaBank 4.25% Fixed due August 1, 2018
Debt Instrument [Line Items]
Prepayment penalties (as a percent)								2.00%
Prepayment penalty period after July 26, 2017 until February 1, 2018 | Mortgage loans | MetaBank 4.25% Fixed due August 1, 2018
Debt Instrument [Line Items]
Prepayment penalties (as a percent)								1.00%
LIBOR | Mortgage loans | Bank Of Cascades Variable due December 19, 2024, Note A
Debt Instrument [Line Items]
Interest rate margin on variable rate basis				2.00%
LIBOR | Mortgage loans | Compass Bank 3.17% Variable due May 6, 2020
Debt Instrument [Line Items]
Interest rate margin on variable rate basis					2.40%
Hampton Inn | Santa Barbara (Goleta), CA
Debt Instrument [Line Items]
Number of guestrooms | Room							98
Hampton Inn | Santa Barbara (Goleta), CA | Mortgage loans | U.S. Bank, NA 6.13% Fixed due November 11, 2021
Debt Instrument [Line Items]
Debt assumed							$ 12,000,000
MetaBank | Secured debt | Non-recourse loan
Debt Instrument [Line Items]
Stated interest rate									4.44%
Loan amount										$ 47,600,000.0
Loan increase	$ 22,600,000	$ 25,000,000
Debt interest only payments term									18 months
Loan amortization period after interest only payments period									25 years