Debt (Details Textual) - USD ($)							3 Months Ended		6 Months Ended
		Jun. 10, 2015	May. 19, 2015	Apr. 13, 2015	Mar. 05, 2015	Dec. 17, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jul. 23, 2015	Dec. 31, 2014	Oct. 31, 2014
Line of Credit Facility [Line Items]
Proceeds from Issuance of Unsecured Debt									$ 100,000,000	$ 0
Outstanding borrowings under the credit facility	[1]						$ 310,000,000		310,000,000			$ 50,000,000
Term loans	[2]						400,000,000		400,000,000			300,000,000
Borrowings under senior credit facility									380,000,000	40,000,000
Unrealized gain (loss) on derivative instruments							4,077,000	$ (462,000)	(92,000)	(578,000)
Repayments of mortgage debt									55,420,000	4,516,000
Estimated fair value of debt							444,600,000		444,600,000			503,900,000
The Nines Hotel Portland [Member]
Line of Credit Facility [Line Items]
Repayments of mortgage debt					$ 50,700,000
Interest Rate Swap [Member]
Line of Credit Facility [Line Items]
Notional amount							300,000,000.0		300,000,000.0				$ 100,000,000
Aggregate asset							1,700,000		1,700,000
Aggregate liability							2,100,000		2,100,000
Reclassification from AOCI to interest expense							1,200,000	100,000	2,000,000	300,000
Expected reclassifications in next 12 months									$ 4,100,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration date	[1]								Jan. 15, 2019
Revolving Credit Facility [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Increase in borrowing capacity			$ 150,000,000
Borrowing capacity			$ 750,000,000				450,000,000		$ 450,000,000
Maximum borrowing capacity							1,000,000,000		1,000,000,000
Outstanding borrowings under the credit facility							310,000,000		310,000,000			50,000,000
Unused commitment fees							200,000	$ 200,000	$ 300,000	$ 300,000
Revolving Credit Facility [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Annual rate of unused commitment fee									0.20%
Revolving Credit Facility [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus									1.55%
Revolving Credit Facility [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Annual rate of unused commitment fee									0.30%
Revolving Credit Facility [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus									2.30%
Term Loan [Member]
Line of Credit Facility [Line Items]
Expiration date									Jan. 15, 2020
Term Loan [Member] | First Term Loan [Member]
Line of Credit Facility [Line Items]
Term loans	[2]						300,000,000		$ 300,000,000			300,000,000
Borrowings under senior credit facility						$ 200,000,000.0
Term Loan [Member] | First Term Loan [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus									1.50%
Term Loan [Member] | First Term Loan [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus									2.25%
Term Loan [Member] | Second Term Loan [Member]
Line of Credit Facility [Line Items]
Borrowing capacity				$ 100,000,000
Expiration date									Apr. 15, 2022
Proceeds from Issuance of Unsecured Debt				$ 100,000,000
Term loans	[2]						100,000,000		$ 100,000,000			0
Term Loan [Member] | Second Term Loan [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus				1.70%
Term Loan [Member] | Second Term Loan [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus				2.55%
Term Loan [Member] | Third Term Loan [Member]
Line of Credit Facility [Line Items]
Borrowing capacity		$ 125,000,000
Expiration date									Jan. 10, 2021
Maximum borrowing capacity		$ 250,000,000
Term loans	[2]						$ 0		$ 0			$ 0
Term Loan [Member] | Third Term Loan [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus		1.45%
Term Loan [Member] | Third Term Loan [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility borrowings LIBOR rate plus		2.20%
Term Loan [Member] | Interest Rate Swap [Member] | Second Term Loan [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate							3.46%		3.46%
Term Loan [Member] | Interest Rate Swap [Member] | Term Loan Through July 12, 2017 [Member]
Line of Credit Facility [Line Items]
Effective interest rate							2.93%		2.93%
Term Loan [Member] | Interest Rate Swap [Member] | Term Loan July 13, 2017 through January 15, 2020 [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate							3.51%		3.51%
Term Loan [Member] | Unsecured Debt [Member] | Senior Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity							$ 300,000,000		$ 300,000,000
Subsequent Event [Member] | Term Loan [Member] | Third Term Loan [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings under the credit facility											$ 125,000,000
Subsequent Event [Member] | Term Loan [Member] | Interest Rate Swap [Member] | Third Term Loan [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate											3.29%

[1] Borrowings bear interest at floating rates equal to, at the Company's option, either (i) LIBOR plus an applicable margin or (ii) an Adjusted Base Rate (as defined in the senior unsecured credit agreement) plus an applicable margin. The Company has two six-month extension options.

[2] Borrowings under the term loan facilities bear interest at floating rates equal to, at the Company's option, either (i) LIBOR plus an applicable margin or (ii) a Base Rate plus an applicable margin. The Company entered into interest rate swaps to effectively fix the interest rate for the First Term Loan, Second Term Loan and Third Term Loan. At June 30, 2015 and December 31, 2014, the Company had interest rate swaps on the full amounts outstanding. See "Derivative and Hedging Activities" above.