Fair Value of Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of assets measured on a non-recurring basis at fair value, categorized by the level of inputs used in the valuation assets

The table below presents certain of our assets measured at fair value at December 31, 2017, categorized by the level of inputs, as defined in the fair value hierarchy under GAAP, used in the valuation of each asset:

			Fair Value at Reporting Date Using
			Quoted Prices in				Significant
	Estimated		Active Markets for		Significant Other		Unobservable
	Fair		Identical Assets		Observable Inputs		Inputs
Description	Value		(Level 1)		(Level 2)		(Level 3)
Recurring Fair Value Measurements Assets:
Investment in RMR Inc. (1)	$	72,005	$	72,005	$	—	$	—
Non-Recurring Fair Value Measurements Assets:
One property (2)	$	19,667	$	—	$	19,667	$	—

(1) Our 1,214,225 shares of class A common stock of RMR Inc., which are included in other assets in our consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs as defined in the fair value hierarchy under GAAP).  Our historical cost basis for these shares is $26,888 as of December 31, 2017.  The net unrealized gain of $45,117 for these shares as of December 31, 2017 is included in cumulative other comprehensive income (loss) in our consolidated balance sheets.

(2) We estimated the fair value of a property we agreed to sell located in Minneapolis, MN at December 31, 2017 based upon the selling price agreed to with a third party (Level 2 inputs as defined in the fair value hierarchy under GAAP). See Note 5 for further details.

Schedule of fair value and carrying value of financial instruments

At December 31, 2017 and December 31, 2016, the fair values of our financial instruments approximated their carrying values in our consolidated financial statements due to their short term nature or variable interest rates, except as follows:

	As of December 31, 2017				As of December 31, 2016
	Carrying  Amount (1)		Fair Value		Carrying  Amount (1)		Fair Value
Senior unsecured notes, 3.750% interest rate, due in 2019	$	348,096	$	354,993	$	346,952	$	354,078
Senior unsecured notes, 5.875% interest rate, due in 2046	300,232		320,416		299,892		292,268
Senior unsecured notes, 4.000% interest rate, due in 2022	295,812		302,655		—		—
Mortgage note payable, 4.050% interest rate, due in 2030(2)(3)	64,293		65,198		—		—
Mortgage note payable, 5.720% interest rate, due in 2020(2)(3)	36,085		36,332		—		—
Mortgage note payable, 4.220% interest rate, due in 2022(2)(3)	27,906		28,432		—		—
Mortgage note payable, 4.800% interest rate, due in 2023(2)(3)	25,501		25,904		—		—
Mortgage note payable, 5.877% interest rate, due in 2021(2)	13,620		14,565		13,841		14,492
Mortgage note payable, 7.000% interest rate, due in 2019(2)	8,391		8,555		8,778		9,188
Mortgage note payable, 8.150% interest rate, due in 2021(2)	4,111		4,340		5,218		5,575
Mortgage note payable, 4.260% interest rate, due in 2020(2)(3)	3,193		3,216		—		—
	$	1,127,240	$	1,164,606	$	674,681	$	675,601

(1) Carrying amount includes certain unamortized debt issuance costs and unamortized premiums and discounts.

(2) We assumed these mortgages in connection with our acquisitions of the encumbered properties.  The stated interest rates for these mortgage debts are the contractually stated rates.  We recorded the assumed mortgages at estimated fair value on the date of acquisition and we are amortizing the fair value premiums, if any, to interest expense over the respective terms of the mortgages to reduce interest expense to the estimated market interest rates as of the date of acquisition.

(3) In connection with the FPO Transaction, we assumed five fixed rate mortgage notes with an aggregate principal balance of $167,548. We recorded these mortgage notes at their estimated fair value aggregating $167,936 on the date of acquisition.