Indebtedness (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of additional outstanding debt

At December 31, 2017 and 2016, our outstanding senior unsecured notes and secured debt consisted of the following:

				December 31, 2017				December 31, 2016
Senior Unsecured Notes	Coupon		Maturity	Face Amount		Unamortized Discount		Face Amount		Unamortized Discount
Senior unsecured notes	3.250	%	2019	$	400,000	$	78	$	400,000	$	138
Senior unsecured notes	6.750	%	2020	200,000		488		200,000		703
Senior unsecured notes	6.750	%	2021	300,000		2,093		300,000		2,627
Senior unsecured notes	4.750	%	2024	250,000		500		250,000		579
Senior unsecured notes	5.625	%	2042	350,000		—		350,000		—
Senior unsecured notes	6.250	%	2046	250,000		—		250,000		—
Total senior unsecured notes				$	1,750,000	$	3,159	$	1,750,000	$	4,047

Schedule of secured and other debt

	Principal Balance as of							Number of Properties as Collateral	Net Book Value of Collateral as of
	December 31,								December 31,
Secured and Other Debt	2017(1)		2016(1)		Interest Rate		Maturity	At December 31, 2017	2017		2016
Mortgage(2)	$	—	$	10,653	6.15	%	Aug 17	—	$	—	$	14,162
Mortgage(2)	—		8,686		6.73	%	Apr 18	—	—		10,656
Mortgage notes	12,552		12,772		6.31	%	Oct 18	1	16,470		16,827
Mortgage notes	11,858		12,061		6.24	%	Oct 18	1	15,025		15,453
Mortgage note	67,749		69,953		4.47	%	Oct 18	10	175,975		180,933
Mortgage note	6,430		6,565		4.69	%	Jan 19	1	9,477		9,687
Mortgage note	43,558		44,462		3.79	%	Jul 19	4	62,596		64,154
Mortgage note(2)	—		279,505		6.71	%	Sep 19	—	—		235,068
Mortgage note	2,603		3,128		7.49	%	Jan 22	1	15,099		15,360
Mortgage note	13,741		14,300		6.28	%	Jul 22	1	24,414		24,834
Mortgage note	11,392		11,594		4.85	%	Oct 22	1	21,065		21,529
Mortgage notes(3)	620,000		620,000		3.53	%	Aug 26	1	764,622		785,805
Mortgage note	2,395		2,819		6.25	%	Feb 33	1	4,473		4,267
Mortgage note(2)	—		8,882		5.95	%	Aug 37	—	—		8,656
Mortgage note(4)	4,338		4,427		4.38	%	Sep 43	1	7,290		7,202
Capital Leases	10,694		11,466		7.70	%	Apr 26	2	18,525		18,968
Total secured	$	807,310	$	1,121,273				25	$	1,135,031	$	1,433,561

(1) The principal balances are the amounts stated in the contracts. In accordance with GAAP, our carrying values and recorded interest expense may be different because of market conditions at the time we assumed certain of these debts. As of December 31, 2017 and 2016, the unamortized net premiums and debt issuance costs on certain of these mortgages were $1,906 and $3,624, respectively.

(2) In 2017, we prepaid these debts.

(3) In July 2016, we entered loan agreements and obtained an aggregate $620,000 secured debt financing that matures in August 2026. These loans are secured by one MOB (two buildings). The property encumbered by these mortgages is owned by a joint venture in which we own a 55% equity interest.

(4) In January 2018, we prepaid this debt.

Schedule of required principal payments on outstanding debt

Required principal payments on our outstanding debt as of December 31, 2017, are as follows:

2018	$	95,811
2019	$	451,592
2020	$	552,869
2021	$	303,102
2022	$	819,227
Thereafter	$	1,480,709