American Campus Communities (ACC) 10-Q 2 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 26, 2018
Document Information [Line Items]
Entity Registrant Name	AMERICAN CAMPUS COMMUNITIES INC
Entity Central Index Key	1,283,630
Trading Symbol	acc
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock Shares Outstanding (in shares)		137,031,488
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Document Information [Line Items]
Entity Registrant Name	American Campus Communities Operating Partnership LP
Entity Central Index Key	1,357,369
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments in real estate:
Investments in real estate, net	$ 6,600,571	$ 6,532,168
Cash and cash equivalents	50,801	41,182
Restricted cash	39,740	23,590
Student contracts receivable, net	45,297	9,170
Other assets	309,639	291,260
Total assets	7,046,048	6,897,370
Liabilities:
Secured mortgage, construction and bond debt, net	920,345	664,020
Accounts payable and accrued expenses	86,481	53,741
Other liabilities	238,921	187,983
Total liabilities	3,299,124	3,266,243
Commitments and contingencies (Note 13)
Redeemable noncontrolling interests	184,654	132,169
American Campus Communities, Inc. and Subsidiaries stockholders’ equity:
Common stock, $0.01 par value, 800,000,000 shares authorized, 136,961,885 and 136,362,728 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	1,370	1,364
Additional paid in capital	4,456,208	4,326,910
Common stock held in rabbi trust, 69,603 and 63,778 shares at September 30, 2018 and December 31, 2017, respectively	(3,092)	(2,944)
Accumulated earnings and dividends	(955,310)	(837,644)
Accumulated other comprehensive loss	(1,975)	(2,701)
Total American Campus Communities, Inc. and Subsidiaries stockholders’ equity	3,497,201	3,484,985
Total equity	3,562,270	3,498,958
Partners’ capital:
Accumulated other comprehensive loss	(1,975)	(2,701)
Total liabilities and equity	7,046,048	6,897,370
Owned properties, net
Investments in real estate:
Investments in real estate, net	6,521,705	6,450,364
On-campus participating properties, net
Investments in real estate:
Investments in real estate, net	78,866	81,804
Partially owned properties
American Campus Communities, Inc. and Subsidiaries stockholders’ equity:
Noncontrolling interests - partially owned properties	65,069	13,973
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Investments in real estate:
Investments in real estate, net	6,600,571	6,532,168
Cash and cash equivalents	50,801	41,182
Restricted cash	39,740	23,590
Student contracts receivable, net	45,297	9,170
Other assets	309,639	291,260
Total assets	7,046,048	6,897,370
Liabilities:
Secured mortgage, construction and bond debt, net	920,345	664,020
Accounts payable and accrued expenses	86,481	53,741
Other liabilities	238,921	187,983
Total liabilities	3,299,124	3,266,243
Commitments and contingencies (Note 13)
Redeemable noncontrolling interests	184,654	132,169
American Campus Communities, Inc. and Subsidiaries stockholders’ equity:
Accumulated other comprehensive loss	(1,975)	(2,701)
Partners’ capital:
General partner - 12,222 OP units outstanding at both September 30, 2018 and December 31, 2017	56	67
Limited partner - 137,019,266 and 136,414,284 OP units outstanding at September 30, 2018 and December 31, 2017, respectively	3,499,120	3,487,619
Accumulated other comprehensive loss	(1,975)	(2,701)
Total partners’ capital	3,497,201	3,484,985
Total capital	3,562,270	3,498,958
Total liabilities and equity	7,046,048	6,897,370
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Owned properties, net
Investments in real estate:
Investments in real estate, net	6,521,705	6,450,364
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | On-campus participating properties, net
Investments in real estate:
Investments in real estate, net	78,866	81,804
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Partially owned properties
Partners’ capital:
Noncontrolling interests - partially owned properties	65,069	13,973
Unsecured notes, net
Liabilities:
Unsecured debt	1,587,796	1,585,855
Unsecured notes, net | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Liabilities:
Unsecured debt	1,587,796	1,585,855
Unsecured term loans, net
Liabilities:
Unsecured debt	198,681	647,044
Unsecured term loans, net | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Liabilities:
Unsecured debt	198,681	647,044
Unsecured revolving credit facility
Liabilities:
Unsecured debt	266,900	127,600
Unsecured revolving credit facility | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Liabilities:
Unsecured debt	$ 266,900	$ 127,600

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	800,000,000	800,000,000
Common stock, shares issued (in shares)	136,961,885	136,362,728
Common stock, shares outstanding (in shares)	136,961,885	136,362,728
Common stock held in Rabbi Trust (in shares)	69,603	63,778
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
General partner, OP units outstanding (in shares)	12,222	12,222
Limited partner, OP units outstanding (in shares)	137,019,266	136,414,284
Investments in real estate, net
Consolidated variable interest entities' assets	$ 954,095	$ 438,670
Investments in real estate, net | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Consolidated variable interest entities' assets	954,095	438,670
Cash, cash equivalents and restricted cash
Consolidated variable interest entities' assets	58,108	12,812
Cash, cash equivalents and restricted cash | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Consolidated variable interest entities' assets	58,108	12,812
Other assets
Consolidated variable interest entities' assets	6,968	3,134
Other assets | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Consolidated variable interest entities' assets	6,968	3,134
Secured mortgage and construction debt, net
Consolidated variable interest entities' liabilities	378,338	50,993
Secured mortgage and construction debt, net | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Consolidated variable interest entities' liabilities	378,338	50,993
Accounts payable, accrued expenses and other liabilities
Consolidated variable interest entities' liabilities	59,740	25,200
Accounts payable, accrued expenses and other liabilities | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Consolidated variable interest entities' liabilities	$ 59,740	$ 25,200

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Total revenues	$ 213,469	$ 196,938	$ 634,937	$ 568,884
Operating expenses (income):
Third-party development and management services	3,831	3,879	11,573	11,789
General and administrative	7,183	8,684	27,055	25,200
Depreciation and amortization	66,131	61,125	194,447	169,391
Ground/facility leases	2,951	2,329	8,526	7,151
Provision for real estate impairment	0	0	0	15,317
Other operating income	0	0	(2,648)	0
Total operating expenses	191,968	179,363	532,176	489,480
Operating income	21,501	17,575	102,761	79,404
Nonoperating income (expenses):
Interest income	1,274	1,259	3,740	3,723
Interest expense	(25,185)	(18,654)	(72,207)	(47,944)
Amortization of deferred financing costs	(1,116)	(1,146)	(4,744)	(3,197)
Gain (loss) from disposition of real estate	0	0	42,314	(632)
Loss from early extinguishment of debt	0	0	(784)	0
Other nonoperating income	570	0	570	0
Total nonoperating expenses	(24,457)	(18,541)	(31,111)	(48,050)
(Loss) income before income taxes	(2,956)	(966)	71,650	31,354
Income tax provision	219	(267)	(2,147)	(791)
Net (loss) income	(2,737)	(1,233)	69,503	30,563
Net income attributable to noncontrolling interests	392	(79)	88	(587)
Net (loss) income attributable to ACC, Inc. and Subsidiaries common stockholders	(2,345)	(1,312)	69,591	29,976
Other comprehensive income
Change in fair value of interest rate swaps and other	81	233	726	872
Comprehensive (loss) income	$ (2,264)	$ (1,079)	$ 70,317	$ 30,848
Weighted-average common shares outstanding
Basic (in shares)	137,022,012	136,421,198	136,742,094	134,708,361
Diluted (in shares)	137,022,012	136,421,198	137,660,802	135,585,850
Weighted-average common units outstanding
Distributions declared per common share (in dollars per share)	$ 0.46	$ 0.44	$ 1.36	$ 1.30
Owned properties
Revenues:
Owned properties and on-campus participating properties revenue	$ 202,834	$ 183,569	$ 597,854	$ 531,556
Operating expenses (income):
Operating expenses	107,997	99,423	282,193	249,552
On-campus participating properties
Revenues:
Owned properties and on-campus participating properties revenue	6,980	6,799	23,605	23,128
Operating expenses (income):
Operating expenses	3,875	3,923	11,030	11,080
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Revenues:
Total revenues	213,469	196,938	634,937	568,884
Operating expenses (income):
Third-party development and management services	3,831	3,879	11,573	11,789
General and administrative	7,183	8,684	27,055	25,200
Depreciation and amortization	66,131	61,125	194,447	169,391
Ground/facility leases	2,951	2,329	8,526	7,151
Provision for real estate impairment	0	0	0	15,317
Other operating income	0	0	(2,648)	0
Total operating expenses	191,968	179,363	532,176	489,480
Operating income	21,501	17,575	102,761	79,404
Nonoperating income (expenses):
Interest income	1,274	1,259	3,740	3,723
Interest expense	(25,185)	(18,654)	(72,207)	(47,944)
Amortization of deferred financing costs	(1,116)	(1,146)	(4,744)	(3,197)
Gain (loss) from disposition of real estate	0	0	42,314	(632)
Loss from early extinguishment of debt	0	0	(784)	0
Other nonoperating income	570	0	570	0
Total nonoperating expenses	(24,457)	(18,541)	(31,111)	(48,050)
(Loss) income before income taxes	(2,956)	(966)	71,650	31,354
Income tax provision	219	(267)	(2,147)	(791)
Net (loss) income	(2,737)	(1,233)	69,503	30,563
Net (loss) income attributable to ACC, Inc. and Subsidiaries common stockholders	(2,324)	(1,290)	70,168	30,304
Series A preferred unit distributions	(31)	(31)	(93)	(93)
Net (loss) income attributable to common unitholders	(2,355)	(1,321)	70,075	30,211
Other comprehensive income
Change in fair value of interest rate swaps and other	81	233	726	872
Comprehensive (loss) income	$ (2,274)	$ (1,088)	$ 70,801	$ 31,083
Net (loss) income per share attributable to ACC, Inc. and Subsidiaries common stockholders
Basic and diluted (in dollars per share)	$ (0.02)	$ (0.01)	$ 0.50	$ 0.21
Net (loss) income per unit attributable to common unitholders
Basic and diluted (in dollars per share)	$ (0.02)	$ (0.01)	$ 0.50	$ 0.21
Weighted-average common units outstanding
Basic (in units)	137,624,276	137,432,872	137,573,422	135,731,609
Diluted (in units)	137,624,276	137,432,872	138,492,130	136,609,098
Distributions declared per common unit (in dollars per unit)	$ 0.46	$ 0.44	$ 1.36	$ 1.3
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Owned properties
Revenues:
Owned properties and on-campus participating properties revenue	$ 202,834	$ 183,569	$ 597,854	$ 531,556
Operating expenses (income):
Operating expenses	107,997	99,423	282,193	249,552
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | On-campus participating properties
Revenues:
Owned properties and on-campus participating properties revenue	6,980	6,799	23,605	23,128
Operating expenses (income):
Operating expenses	3,875	3,923	11,030	11,080
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Partially owned properties
Nonoperating income (expenses):
Net income attributable to noncontrolling interests	413	(57)	665	(259)
Third-party development services
Revenues:
Contract with customer, revenue	835	3,566	3,883	4,697
Third-party development services | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Revenues:
Contract with customer, revenue	835	3,566	3,883	4,697
Third-party management services
Revenues:
Contract with customer, revenue	2,128	2,291	7,311	7,193
Third-party management services | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Revenues:
Contract with customer, revenue	2,128	2,291	7,311	7,193
Resident services
Revenues:
Contract with customer, revenue	692	713	2,284	2,310
Resident services | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Revenues:
Contract with customer, revenue	$ 692	$ 713	$ 2,284	$ 2,310

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY/ CAPITAL - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Shares	Additional Paid in Capital	Common Shares Held in Rabbi Trust	Accumulated Earnings and Dividends	Accumulated Other Comprehensive Loss	Noncontrolling Interests - Partially Owned PropertiesPartially owned properties	AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.	AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.Accumulated Other Comprehensive Loss	AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.Noncontrolling Interests - Partially Owned PropertiesPartially owned properties	General PartnerAMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.	Limited PartnerAMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Equity, December 31, 2017 (in shares) at Dec. 31, 2017		136,362,728		63,778
Equity, December 31, 2017 at Dec. 31, 2017	$ 3,498,958	$ 1,364	$ 4,326,910	$ (2,944)	$ (837,644)	$ (2,701)	$ 13,973
Capital, December 31, 2017 (in units) at Dec. 31, 2017											12,222	136,414,284
Capital, December 31, 2017 at Dec. 31, 2017								$ 3,498,958	$ (2,701)	$ 13,973	$ 67	$ 3,487,619
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to reflect redeemable limited partners’ interest at fair value	(65,857)		(65,857)					(65,857)				$ (65,857)
Amortization of restricted stock awards and vesting of restricted stock units (in shares)		27,376										27,376
Amortization of restricted stock awards and vesting of restricted stock units	9,922		9,922					9,922				$ 9,922
Vesting of restricted stock awards (in shares)		165,263										165,263
Vesting of restricted stock awards	(2,756)	$ 2	(2,758)					(2,756)				$ (2,756)
Distributions to common and restricted stockholders	(187,257)				(187,257)
Distributions								(187,257)			(17)	(187,240)
Contributions by noncontrolling interests - partially owned properties	212,481							212,481		212,481
Distributions to noncontrolling interests - partially owned properties	(151,271)						(151,271)	(151,271)		(151,271)
Change in ownership of consolidated subsidiary	165,043		174,515				(9,472)	165,043		(9,472)		$ 174,515
Conversion of common and preferred operating partnership units to common stock (in shares)		412,343										412,343
Conversion of common and preferred operating partnership units to common stock	13,332	$ 4	13,328					13,332				$ 13,332
Change in fair value of interest rate swaps and other	726					726		726	726
Deposits to deferred compensation plan, net of withdrawals (in shares)		(5,825)		5,825
Deposits to deferred compensation plan, net of withdrawals	0		148	$ (148)
Net income (loss)	68,949				69,591		(642)	68,949		(642)	$ 6	$ 69,585
Equity, June 30, 2018 (in shares) at Sep. 30, 2018		136,961,885		69,603
Equity, September 30, 2018 at Sep. 30, 2018	$ 3,562,270	$ 1,370	$ 4,456,208	$ (3,092)	$ (955,310)	$ (1,975)	$ 65,069
Capital, June 30, 2018 (in units) at Sep. 30, 2018											12,222	137,019,266
Capital, September 30, 2018 at Sep. 30, 2018								$ 3,562,270	$ (1,975)	$ 65,069	$ 56	$ 3,499,120

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Payments for Repurchase of Redeemable Noncontrolling Interest	$ 10,486	$ 0
Operating activities
Net income	69,503	30,563
Gain (Loss) on Sale of Properties	42,314	(632)
Adjustments to reconcile net income to net cash provided by operating activities:
Loss from early extinguishment of debt	784	0
Provision for real estate impairment	0	15,317
Depreciation and amortization	194,447	169,391
Amortization of deferred financing costs and debt premiums/discounts	954	(2,691)
Share-based compensation	9,922	11,401
Income tax provision	2,147	791
Amortization of interest rate swap terminations and other	308	308
Changes in operating assets and liabilities:
Student contracts receivable, net	(36,584)	(6,775)
Other assets	(16,739)	(2,536)
Accounts payable and accrued expenses	30,214	(293)
Other liabilities	54,291	29,581
Net cash provided by operating activities	266,933	245,689
Investing activities
Proceeds from disposition of properties	242,284	24,462
Cash paid for acquisition of operating and under development properties	0	(302,318)
Cash paid for land acquisitions	(26,534)	(8,886)
Investment in direct financing lease, net	0	(759)
Proceeds from insurance settlement	1,649	0
Purchase of corporate furniture, fixtures and equipment	(2,527)	(4,997)
Net cash used in investing activities	(216,111)	(769,045)
Financing activities
Proceeds from sale of common stock	0	190,912
Offering costs	0	(2,374)
Pay-off of mortgage and construction loans	(146,165)	(99,185)
Defeasance costs related to early extinguishment of debt	(2,726)	0
Pay-off of unsecured term loans	(450,000)	0
Proceeds from unsecured term loans	0	500,000
Proceeds from revolving credit facility	882,800	974,300
Paydowns of revolving credit facility	(743,500)	(807,160)
Proceeds from construction loans	88,004	10,812
Proceeds from mortgage loans	330,000	0
Scheduled principal payments on debt	(9,728)	(10,582)
Debt issuance and assumption costs	(656)	(7,335)
Contributions by noncontrolling interests	379,901	11,526
Taxes paid on net-share settlements	(2,756)	(4,920)
Distributions to common and restricted stockholders	(187,257)	(176,199)
Distributions to noncontrolling interests	(152,484)	(61,231)
Net cash (used in) provided by financing activities	(25,053)	518,564
Net change in cash, cash equivalents, and restricted cash	25,769	(4,792)
Cash, cash equivalents, and restricted cash at beginning of period	64,772	46,957
Cash, cash equivalents, and restricted cash at end of period	90,541	42,165
Reconciliation of cash, cash equivalents, and restricted cash to the consolidated balance sheets
Total cash, cash equivalents, and restricted cash at end of period	64,772	46,957
Supplemental disclosure of non-cash investing and financing activities
Loans assumed in connection with property acquisitions	0	(80,296)
Conversion of common and preferred operating partnership units to common stock	13,332	154
Non-cash contribution from noncontrolling interest	8,729	120,618
Non-cash consideration exchanged in purchase of land parcel	0	(3,071)
Change in accrued construction in progress	(1,507)	24,753
Change in fair value of derivative instruments, net	418	564
Change in fair value of redeemable noncontrolling interests	(65,857)	5,943
Change in ownership of consolidated subsidiary	(175,529)	0
Supplemental disclosure of cash flow information
Cash paid for interest, net of amounts capitalized	68,970	49,562
Owned properties
Investing activities
Investments in owned properties under development	(55,814)	(64,464)
Owned Properties Under Development [Member]
Investing activities
Investments in owned properties under development	(372,251)	(409,174)
On-campus participating properties
Investing activities
Investments in owned properties under development	(2,918)	(2,909)
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Payments for Repurchase of Redeemable Noncontrolling Interest	10,486
Payments to Noncontrolling Interests		0
Operating activities
Net income	69,503	30,563
Gain (Loss) on Sale of Properties	42,314	(632)
Adjustments to reconcile net income to net cash provided by operating activities:
Loss from early extinguishment of debt	784	0
Provision for real estate impairment	0	15,317
Depreciation and amortization	194,447	169,391
Amortization of deferred financing costs and debt premiums/discounts	954	(2,691)
Share-based compensation	9,922	11,401
Income tax provision	2,147	791
Amortization of interest rate swap terminations and other	308	308
Changes in operating assets and liabilities:
Student contracts receivable, net	(36,584)	(6,775)
Other assets	(16,739)	(2,536)
Accounts payable and accrued expenses	30,214	(293)
Other liabilities	54,291	29,581
Net cash provided by operating activities	266,933	245,689
Investing activities
Proceeds from disposition of properties	242,284	24,462
Cash paid for acquisition of operating and under development properties	0	(302,318)
Cash paid for land acquisitions	(26,534)	(8,886)
Investment in direct financing lease, net	0	(759)
Proceeds from insurance settlement	1,649	0
Purchase of corporate furniture, fixtures and equipment	(2,527)	(4,997)
Net cash used in investing activities	(216,111)	(769,045)
Financing activities
Proceeds from issuance of common units in exchange for contributions, net	0	188,538
Pay-off of mortgage and construction loans	(146,165)	(99,185)
Defeasance costs related to early extinguishment of debt	(2,726)	0
Pay-off of unsecured term loans	(450,000)	0
Proceeds from unsecured term loans	0	500,000
Proceeds from revolving credit facility	882,800	974,300
Paydowns of revolving credit facility	(743,500)	(807,160)
Proceeds from construction loans	88,004	10,812
Proceeds from mortgage loans	330,000	0
Scheduled principal payments on debt	(9,728)	(10,582)
Debt issuance and assumption costs	(656)	(7,335)
Contributions by noncontrolling interests	379,901	11,526
Taxes paid on net-share settlements	(2,756)	(4,920)
Net cash (used in) provided by financing activities	(25,053)	518,564
Net change in cash, cash equivalents, and restricted cash	25,769	(4,792)
Cash, cash equivalents, and restricted cash at beginning of period	64,772	46,957
Cash, cash equivalents, and restricted cash at end of period	90,541	42,165
Reconciliation of cash, cash equivalents, and restricted cash to the consolidated balance sheets
Total cash, cash equivalents, and restricted cash at end of period	64,772	46,957
Supplemental disclosure of non-cash investing and financing activities
Loans assumed in connection with property acquisitions	0	(80,296)
Conversion of common and preferred operating partnership units to common stock	13,332	154
Non-cash contribution from noncontrolling interest	8,729	120,618
Non-cash consideration exchanged in purchase of land parcel	0	(3,071)
Change in accrued construction in progress	(1,507)	24,753
Change in fair value of derivative instruments, net	418	564
Change in fair value of redeemable noncontrolling interests	(65,857)	5,943
Change in ownership of consolidated subsidiary	175,529	0
Supplemental disclosure of cash flow information
Cash paid for interest, net of amounts capitalized	68,970	49,562
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Common and preferred units
Financing activities
Distributions paid	(187,177)	(176,404)
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Unvested restricted awards
Financing activities
Distributions paid	(1,293)	(1,217)
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Partially owned properties
Financing activities
Distributions paid	(151,271)	(59,809)
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | On-campus participating properties
Investing activities
Investments in owned properties under development	$ (2,918)	$ (2,909)

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business American Campus Communities, Inc. (“ACC”) is a real estate investment trust (“REIT”) that commenced operations effective with the completion of an initial public offering (“IPO”) on August 17, 2004. Through ACC’s controlling interest in American Campus Communities Operating Partnership, L.P. (“ACCOP”), ACC is one of the largest owners, managers and developers of high quality student housing properties in the United States in terms of beds owned and under management. ACC is a fully integrated, self-managed and self-administered equity REIT with expertise in the acquisition, design, financing, development, construction management, leasing and management of student housing properties. ACC’s common stock is publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “ACC.” The general partner of ACCOP is American Campus Communities Holdings, LLC (“ACC Holdings”), an entity that is wholly-owned by ACC. As of September 30, 2018 , ACC Holdings held an ownership interest in ACCOP of less than 1% . The limited partners of ACCOP are ACC and other limited partners consisting of current and former members of management and nonaffiliated third parties. As of September 30, 2018 , ACC owned an approximate 99.5% limited partnership interest in ACCOP. As the sole member of the general partner of ACCOP, ACC has exclusive control of ACCOP’s day-to-day management. Management operates ACC and ACCOP as one business. The management of ACC consists of the same members as the management of ACCOP. ACC consolidates ACCOP for financial reporting purposes, and ACC does not have significant assets other than its investment in ACCOP. Therefore, the assets and liabilities of ACC and ACCOP are the same on their respective financial statements. References to the “Company” means collectively ACC, ACCOP and those entities/subsidiaries owned or controlled by ACC and/or ACCOP. References to the “Operating Partnership” mean collectively ACCOP and those entities/subsidiaries owned or controlled by ACCOP. Unless otherwise indicated, the accompanying Notes to the Consolidated Financial Statements apply to both the Company and the Operating Partnership. As of September 30, 2018 , the Company’s property portfolio contained 168 properties with approximately 103,500 beds. The Company’s property portfolio consisted of 131 owned off-campus student housing properties that are in close proximity to colleges and universities, 32 American Campus Equity (“ACE®”) properties operated under ground/facility leases with 15 university systems and five on-campus participating properties operated under ground/facility leases with the related university systems. Of the 168 properties, five were under development as of September 30, 2018 , and when completed will consist of a total of approximately 3,200 beds. The Company’s communities contain modern housing units and are supported by a resident assistant system and other student-oriented programming, with many offering resort-style amenities. Through one of ACC’s taxable REIT subsidiaries (“TRSs”), the Company also provides construction management and development services, primarily for student housing properties owned by colleges and universities, charitable foundations, and others. As of September 30, 2018 , also through one of ACC’s TRSs, the Company provided third-party management and leasing services for 34 properties that represented approximately 28,400 beds. Third-party management and leasing services are typically provided pursuant to management contracts that have initial terms that range from one to five years . As of September 30, 2018 , the Company’s total owned and third-party managed portfolio included 202 properties with approximately 131,900 beds.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and use of Estimates The accompanying consolidated financial statements, presented in U.S. dollars, are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the date of the financial statements, and revenue and expenses during the reporting periods. The Company’s actual results could differ from those estimates and assumptions. All material intercompany transactions among consolidated entities have been eliminated. All dollar amounts in the tables herein, except share, per share, unit and per unit amounts, are stated in thousands unless otherwise indicated. Principles of Consolidation The Company’s consolidated financial statements include its accounts and the accounts of other subsidiaries and joint ventures (including partnerships and limited liability companies) over which it has control. Investments acquired or created are evaluated based on the accounting guidance relating to variable interest entities (“VIEs”), which requires the consolidation of VIEs in which the Company is considered to be the primary beneficiary. If the investment is determined not to be a VIE, then the investment is evaluated for consolidation using the voting interest model. Recently Issued Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2016-02 (“ASU 2016-02”), “Leases (Topic 842): Amendments to the FASB Accounting Standards Codification.” ASU 2016-02 outlines principles for the recognition, measurement, presentation and disclosure of leases. Subsequent to the issuance of ASU 2016-02, the FASB issued additional ASUs clarifying aspects of the new lease accounting standard, which will be effective upon adoption of ASU 2016-02. The Company plans to adopt ASU 2016-02 as of January 1, 2019, utilizing the “modified retrospective” method. While the Company is still completing its evaluation of the effect that the new standard will have on its consolidated financial statements and related disclosures, the anticipated impact of ASU 2016-02 is as follows: As Lessee: • Under the new standard, lessees will classify leases as either operating or finance leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized on a straight-line basis over the term of the lease (operating lease) or on an effective interest method (finance lease). In addition, ASU 2016-02 requires lessees to recognize right-of-use assets and related lease liabilities for leases with a term greater than 12 months regardless of their lease classification. As of September 30, 2018, the Company is a lessee under 24 ground leases and 2 corporate office headquarters leases for which it will recognize a right of use asset and lease liability upon adoption. We are currently determining the appropriate discount rate to utilize in our calculations of the right-of-use asset and lease liability, and, as such, we have not finalized our calculations as of September 30, 2018. Details of the future minimum lease payments for leases in existence as of December 31, 2017 are disclosed in Note 15 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2017. • Because the Company’s existing leases under which it is a lessee will continue to be classified as operating leases, the timing and pattern of lease expense recognition (straight-line basis) will remain unchanged. However, for any leases entered into or modified after the adoption date, the leases will need to be evaluated under the new standard and may be classified as finance leases depending on the terms of the transactions. As Lessor: • Under the new standard, the accounting for lessors will remain largely unchanged from current GAAP; however, ASU 2016-02 requires that lessors expense, on an as-incurred basis, certain initial direct costs that are not incremental in negotiating a lease. Under existing standards, these costs are capitalizable and therefore the new lease standard will result in certain of these costs being expensed as incurred after adoption. For the Company, these costs include internal leasing payroll costs incurred for owned and presale development projects, as well as legal expenses incurred when negotiating commercial leases. • The new standard provides a practical expedient that allows lessors to not separate certain lease and non-lease components if certain criteria are met. For the Company’s commercial leases under which the tenants pay for common area maintenance charges, the Company assessed the criteria and determined that the timing and pattern of transfer for common area maintenance and the related rental revenue is the same. Therefore, the Company plans to elect the practical expedient which will result in no change to how revenue from commercial leases is currently recorded. The Company expects to adopt the following additional practical expedients available for implementation: • An entity need not reassess whether any existing or expired contracts are or contain leases; • An entity need not reassess lease classification for any existing or expired leases; • An entity need not reassess initial direct costs for any existing leases; and • Permitted use of hindsight in determining the lease term and in assessing impairment of right of use assets. In addition, the Company does not expect the following accounting pronouncements to have a material effect on its consolidated financial statements: Accounting Standards Update Effective Date ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract” January 1, 2020 ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” January 1, 2020 ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” January 1, 2019 ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” January 1, 2019 ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” January 1, 2020 Recently Adopted Accounting Pronouncements Accounting Standards Update 2016-18 (“ASU 2016-18”), “Statement of Cash Flows: Restricted Cash” On January 1, 2018, the Company adopted ASU 2016-18. The amendments in this update require the change in restricted cash to be reported with cash and cash equivalents when reconciling between beginning and ending amounts in the statements of cash flows. The Company applied the amendments retrospectively to each period presented in the consolidated statements of cash flows of the Company. Prior to the adoption of ASU 2016-18, the Company reported the change in restricted cash within operating, investing, and financing activities in its consolidated statement of cash flows. As a result of the Company’s adoption of this standard and the retrospective application, cash and cash equivalents in the consolidated statements of cash flows as of September 30, 2017 increased by approximately $25.8 million to reflect the inclusion of the restricted cash balance at the end of the period, net cash provided by operating activities for the nine months ended September 30, 2017 increased by approximately $0.6 million , net cash used in investing activities decreased by approximately $1.3 million , and net cash provided by financing activities decreased by approximately $0.9 million . Accounting Standards Update 2014-09 (“ASU 2014-09”), “Revenue From Contracts With Customers (Topic 606)” On January 1, 2018, the Company adopted ASU 2014-09 and all related clarifying Accounting Standards Updates associated with ASU 2014-09. ASU 2014-09 provides a single comprehensive revenue recognition model for contracts with customers (excluding certain contracts, such as lease contracts) to improve comparability within industries. ASU 2014-09 requires an entity to recognize revenue to reflect the transfer of goods or services to customers at an amount the entity expects to be paid in exchange for those goods and services and provide enhanced disclosures, all to provide more comprehensive guidance for transactions such as service revenue and contract modifications. The Company adopted the new revenue standard using the modified retrospective approach, and elected to apply the practical expedient to only assess the recognition of revenue for open contracts during the transition period. The effect of adoption did not have a material impact on the Company’s consolidated financial statements and there was no adjustment to the opening balance of retained earnings at January 1, 2018. The comparative information has not been restated and continues to be reported under the accounting standards in effect for that period. Under the new standard there was a change in the way the Company determines the unit of account for its third-party development projects. Under the previous guidance, the Company segmented revenue recognition between the development and construction phases of its contracts, recognizing each using the proportional performance method and the percentage of completion method, respectively. Under the new guidance, the entire development and construction contract represents a single performance obligation comprised of a series of distinct services to be satisfied over time, and a single transaction price to be recognized over the life of the contract using a time-based measure of progress. Any variable consideration included in the transaction price is estimated using the expected value approach and is only included to the extent that a significant revenue reversal is not likely to occur. The adoption of ASU 2014-09 resulted in differences in the timing and pattern of revenue recognition for such third-party development and construction management contracts; however, the change did not have a material impact on the Company’s consolidated financial statements. Third-party management services revenues consist of base fees earned as a result of managing all aspects of the property’s day-to-day operations, and incentive fees based on the managed property’s operating measures. There was no change in the Company’s recognition of base management fees. Incentive management fees were previously recognized when the incentive criteria had been met. Under the new guidance, incentive fees are estimated using the expected value approach and are included in the transaction price only to the extent that a significant revenue reversal is not likely to occur; however, the change did not have a material impact on the Company’s consolidated financial statements. There was no change to the Company’s revenue recognition methods for ancillary services and other non-lease related revenues as a result of the adoption of ASU 2014-09. Rental income from leasing arrangements is specifically excluded from ASU 2014-09, and is being evaluated as part of the adoption of the lease accounting standard, ASU 2016-02, discussed above. Accounting Standards Update 2017-05 (“ASU 2017-05”), “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets” On January 1, 2018, in conjunction with the adoption of ASU 2014-09, discussed above, the Company adopted ASU 2017-05. The purpose of this ASU is to eliminate the diversity in practice in accounting for derecognition of a nonfinancial asset and in-substance nonfinancial assets (only when the asset or asset group does not meet the definition of a business or the transaction is not a sale to a customer). The adoption of ASU 2017-05 did not have a material impact on the consolidated financial statements given the simplicity of the Company’s historical disposition transactions. Other In addition, on January 1, 2018, the Company adopted the following accounting pronouncements which did not have a material effect on the Company’s consolidated financial statements: • ASU 2017-09, “Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting” • ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” Interim Financial Statements The accompanying interim financial statements are unaudited, but have been prepared in accordance with GAAP for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair presentation of the financial statements of the Company for these interim periods have been included. Because of the seasonal nature of the Company’s operations, the results of operations and cash flows for any interim period are not necessarily indicative of results for other interim periods or for the full year. These financial statements should be read in conjunction with the financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Investments in Real Estate Investments in real estate are recorded at historical cost. Major improvements that extend the life of an asset are capitalized and depreciated over the remaining useful life of the asset. The cost of ordinary repairs and maintenance are charged to expense when incurred. Depreciation and amortization are recorded on a straight-line basis over the estimated useful lives of the assets as follows: Buildings and improvements 7-40 years Leasehold interest - on-campus participating properties 25-34 years (shorter of useful life or respective lease term) Furniture, fixtures and equipment 3-7 years Project costs directly associated with the development and construction of an owned real estate project, which include interest, property taxes, and amortization of deferred financing costs, are capitalized as construction in progress. Upon completion of the project, costs are transferred into the applicable asset category and depreciation commences. Interest totaling approximately $2.6 million and $3.4 million was capitalized during the three months ended September 30, 2018 and 2017 , respectively, and interest totaling approximately $9.6 million and $13.5 million was capitalized during the nine months ended September 30, 2018 and 2017 , respectively. Management assesses whether there has been an impairment in the value of the Company’s investments in real estate whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Impairment is recognized when estimated expected future undiscounted cash flows are less than the carrying value of the property, or when a property meets the criteria to be classified as held for sale, at which time an impairment charge is recognized for any excess of the carrying value of the property over the expected net proceeds from the disposal. The estimation of expected future net cash flows is inherently uncertain and relies on assumptions regarding current and future economics and market conditions. If such conditions change, then an adjustment to the carrying value of the Company’s long-lived assets could occur in the future period in which the conditions change. To the extent that a property is impaired, the excess of the carrying amount of the property over its estimated fair value is charged to earnings. The Company believes that there were no impairments of the carrying values of its investments in real estate as of September 30, 2018 . The Company evaluates each acquisition to determine if the integrated set of assets and activities acquired meet the definition of a business. If either of the following criteria is met, the integrated set of assets and activities acquired would not qualify as a business: • Substantially all of the fair value of the gross assets acquired is concentrated in either a single identifiable asset or a group of similar identifiable assets; or • The integrated set of assets and activities is lacking, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs (i.e. revenue generated before and after the transaction). Property acquisitions deemed to qualify as a business are accounted for as business combinations, and the related acquisition costs are expensed as incurred. The Company allocates the purchase price of properties acquired in business combinations to net tangible and identified intangible assets based on their fair values. Fair value estimates are based on information obtained from a number of sources, including independent appraisals that may be obtained in connection with the acquisition or financing of the respective property, the Company’s own analysis of recently acquired and existing comparable properties in the Company’s portfolio, and other market data. Information obtained about each property, as a result of due diligence, marketing, and leasing activities, is also considered. The value allocated to land is generally based on the actual purchase price if acquired separately, or market research/comparables if acquired as part of an existing operating property. The value allocated to building is based on the fair value determined on an “as-if vacant” basis, which is estimated using a replacement cost approach that relies upon assumptions that the Company believes are consistent with current market conditions for similar properties. The value allocated to furniture, fixtures, and equipment is based on an estimate of the fair value of the appliances and fixtures inside the units. The Company has determined these estimates are primarily based upon unobservable inputs and therefore are considered to be Level 3 inputs within the fair value hierarchy. Acquisitions of properties that do not meet the definition of a business are accounted for as asset acquisitions. The accounting model for asset acquisitions is similar to the accounting model for business combinations except that the acquisition consideration (including transaction costs) is allocated to the individual assets acquired and liabilities assumed on a relative fair value basis. The relative fair values used to allocate the cost of an asset acquisition are determined using the same methodologies and assumptions as those utilized to determine fair value in a business combination. Long-Lived Assets–Held for Sale Long-lived assets to be disposed of are classified as held for sale in the period in which all of the following criteria are met: a. Management, having the authority to approve the action, commits to a plan to sell the asset. b. The asset is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets. c. An active program to locate a buyer and other actions required to complete the plan to sell the asset have been initiated. d. The sale of the asset is probable, and transfer of the asset is expected to qualify for recognition as a completed sale, within one year. e. The asset is being actively marketed for sale at a price that is reasonable in relation to its current fair value. f. Actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Concurrent with this classification, the asset is recorded at the lower of cost or fair value less estimated selling costs, and depreciation ceases. The Company did not have any properties classified as held for sale as of September 30, 2018 . Restricted Cash Restricted cash consists of funds held in trust and invested in low risk investments, generally consisting of government backed securities, as permitted by the indentures of trusts, which were established in connection with three bond issues for the Company’s on-campus participating properties. Additionally, restricted cash includes escrow accounts held by lenders and resident security deposits, as required by law in certain states. Restricted cash also consists of escrow deposits made in connection with potential property acquisitions and development opportunities. These escrow deposits are invested in interest-bearing accounts at federally-insured banks. Realized and unrealized gains and losses are not material for the periods presented. Consolidated VIEs The Company has investments in various entities that qualify as VIEs for accounting purposes and for which the Company is the primary beneficiary and therefore includes the entities in its consolidated financial statements. These VIEs include the Operating Partnership, six joint ventures that own a total of 15 operating properties, two properties subject to presale arrangements, and five properties owned under the on-campus participating property structure. Third-Party Development Services Costs Pre-development expenditures such as architectural fees, permits, and deposits associated with the pursuit of third-party and owned development projects are expensed as incurred, until such time that management believes it is probable that the contract will be executed and/or construction will commence, at which time the Company capitalizes the costs. Because the Company frequently incurs these pre-development expenditures before a financing commitment and/or required permits and authorizations have been obtained, the Company bears the risk of loss of these pre-development expenditures if financing cannot ultimately be arranged on acceptable terms or the Company is unable to successfully obtain the required permits and authorizations. As such, management evaluates the status of third-party and owned projects that have not yet commenced construction on a periodic basis and expenses any deferred costs related to projects whose current status indicates the commencement of construction is unlikely and/or the costs may not provide future value to the Company in the form of revenues. Such write-offs are included in third-party development and management services expenses (in the case of third-party development projects) or general and administrative expenses (in the case of owned development projects) on the accompanying consolidated statements of comprehensive income. As of September 30, 2018 , the Company has deferred approximately $13.7 million in pre-development costs related to third-party and owned development projects that have not yet commenced construction. Such costs are included in other assets on the accompanying consolidated balance sheets. Earnings per Share – Company Basic earnings per share is computed using net income attributable to common stockholders and the weighted average number of shares of the Company’s common stock outstanding during the period. Diluted earnings per share reflects common shares issuable from the assumed conversion of American Campus Communities Operating Partnership Units (“OP Units”) and common share awards granted. Only those items having a dilutive impact on basic earnings per share are included in diluted earnings per share. The following potentially dilutive securities were outstanding for the three and nine months ended September 30, 2018 and 2017 , but were not included in the computation of diluted earnings per share because the effects of their inclusion would be anti-dilutive. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Common OP Units (Note 9) 602,264 1,011,674 831,328 1,023,248 Preferred OP Units (Note 9) 77,513 77,513 77,513 77,513 Unvested restricted stock awards (Note10) 883,595 818,547 — — Total potentially dilutive securities 1,563,372 1,907,734 908,841 1,100,761 The following is a summary of the elements used in calculating basic and diluted earnings per share: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator – basic and diluted earnings per share: Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 Net loss (income) attributable to noncontrolling interests 392 (79 ) 88 (587 ) Net (loss) income attributable to common stockholders (2,345 ) (1,312 ) 69,591 29,976 Amount allocated to participating securities (408 ) (360 ) (1,291 ) (1,217 ) Net (loss) income attributable to common stockholders $ (2,753 ) $ (1,672 ) $ 68,300 $ 28,759 Denominator: Basic weighted average common shares outstanding 137,022,012 136,421,198 136,742,094 134,708,361 Unvested restricted stock awards (Note 10) — — 918,708 877,489 Diluted weighted average common shares outstanding 137,022,012 136,421,198 137,660,802 135,585,850 Earnings per share: Net (loss) income attributable to common stockholders - basic and diluted $ (0.02 ) $ (0.01 ) $ 0.50 $ 0.21 Earnings per Unit – Operating Partnership Basic earnings per OP Unit is computed using net income attributable to common unitholders and the weighted average number of common units outstanding during the period. Diluted earnings per OP Unit reflects the potential dilution that could occur if securities or other contracts to issue OP Units were exercised or converted into OP Units or resulted in the issuance of OP Units and then shared in the earnings of the Operating Partnership. The following is a summary of the elements used in calculating basic and diluted earnings per unit: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator – basic and diluted earnings per unit: Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 Net loss (income) attributable to noncontrolling interests – partially owned properties 413 (57 ) 665 (259 ) Series A preferred unit distributions (31 ) (31 ) (93 ) (93 ) Amount allocated to participating securities (408 ) (360 ) (1,291 ) (1,217 ) Net (loss) income attributable to common unitholders $ (2,763 ) $ (1,681 ) $ 68,784 $ 28,994 Denominator: Basic weighted average common units outstanding 137,624,276 137,432,872 137,573,422 135,731,609 Unvested restricted stock awards (Note 10) — — 918,708 877,489 Diluted weighted average common units outstanding 137,624,276 137,432,872 138,492,130 136,609,098 Earnings per unit: Net (loss) income attributable to common unitholders - basic and diluted $ (0.02 ) $ (0.01 ) $ 0.50 $ 0.21

Acquisitions and Joint Venture

Acquisitions and Joint Venture Investments	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions and Joint Venture Investments	Acquisitions and Joint Venture Investments Presale Development Projects: During the nine months ended September 30, 2018 , the Company entered into two presale agreements to purchase two properties under development. The Company is obligated to purchase the properties for approximately $107.3 million , which includes the contractual purchase price and the cost of elected upgrades, as long as the developer meets certain construction completion deadlines and other closing conditions. Property Location Primary University Served Project Type Beds Scheduled Completion The Flex at Stadium Centre Tallahassee, FL Florida State University Off-campus 340 August 2019 959 Franklin (1) Eugene, OR University of Oregon Off-campus 443 September 2019 783 (1) As part of the presale agreement, the Company provided $15.6 million of mezzanine financing to the project. In August 2018, The Edge - Stadium Centre, a 412 -bed off-campus development property subject to a presale agreement, was completed and acquired by the Company for $42.6 million , including $10.0 million related to the purchase of the land on which the property is built. As the property was consolidated by the Company from the time of execution of the presale agreement with the developer, the closing of the transaction was accounted for as an increase in ownership of a consolidated subsidiary. Property Acquisitions: During the third quarter of 2017, the Company executed an agreement to acquire a portfolio of seven student housing properties from affiliates of Core Spaces and DRW Real Estate Investments (the “Core Transaction”). The transaction included the purchase of 100% of the ownership interests in two operating properties, the purchase of partial ownership interests in two operating properties that completed construction and commenced operations in Fall 2017, and the purchase of partial ownership interests in three properties that completed construction and commenced operations in Fall 2018. The purchase of partial ownership interests was made through a joint venture arrangement. In total, the Core Transaction properties contain 3,776 beds. The initial investment made at closing was $306.0 million and the Company increased its investment by $83.7 million in September 2018. The purchase of the remaining ownership interests in the properties of approximately $ 200.9 million is anticipated to be completed in the fourth quarter 2018 and Fall 2019. During the nine months ended September 30, 2017 , the Company acquired two owned properties containing 982 beds for a total purchase price of approximately $158.5 million , as well as 100% of the ownership interests in two operating properties as part of the Core Transaction described above for $146.1 million . Total cash consideration was approximately $302.3 million . The difference between the contracted purchase price and the cash consideration is due to other assets and liabilities that were not part of the contractual purchase price, but were acquired in the transactions, as well as transaction costs capitalized as part of the acquisitions. Land Acquisitions: In August 2018, the Company purchased a land parcel for a total purchase price of approximately $16.6 million . Total cash consideration was approximately $16.5 million . During the nine months ended September 30, 2017 , the Company purchased five land parcels for a total purchase price of approximately $12.0 million . Total consideration transferred was comprised of approximately $8.9 million of cash consideration and $3.1 million of non-cash consideration, primarily related to the forgiveness of a loan made to the seller during the initial option period. In addition, the Company made an initial investment of $9.0 million in a joint venture that holds a land parcel with fair value of $12.0 million .

Property Dispositions

Property Dispositions	9 Months Ended
	Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Property Dispositions	Property Dispositions Property Dispositions: In May 2018, the Company sold the following portfolio of three owned properties for approximately $245.0 million , resulting in net proceeds of approximately $242.3 million . The combined net gain on the portfolio disposition totaled approximately $42.3 million . Property Location Primary University Served Beds Icon Plaza Los Angeles, CA University of Southern California 253 West 27th Place Los Angeles, CA University of Southern California 475 The Standard Athens, GA University of Georgia 610 1,338 During the nine months ended September 30, 2017 , the Company sold The Province - Dayton, an owned property located near Wright State University in Dayton, Ohio, containing 657 beds for $25.0 million , resulting in net proceeds of approximately $24.5 million . The net loss on this disposition totaled approximately $0.6 million . Concurrent with the classification of this property as held for sale in December 2016, the Company reduced the property’s carrying amount to its estimated fair value less estimated selling costs, and recorded an impairment charge of $4.9 million . Joint Venture Activity : In May 2018, the Company executed an agreement to enter into a joint venture arrangement with Allianz Real Estate (the “ACC / Allianz Joint Venture Transaction”). The transaction included the sale of a partial ownership interest in a portfolio of seven owned properties, containing 4,611 beds, through a joint venture arrangement. The joint venture transaction involved the joint venture partner making a cash contribution of approximately $373.1 million in exchange for a 45% ownership interest. As part of the transaction, the joint venture issued $330 million of secured mortgage debt. For further discussion refer to Note 7 . The joint venture was determined to be a VIE. As the Company retained control of the properties after the joint venture transaction, it was deemed the primary beneficiary. As such, the Company’s contribution of the properties to the joint venture was recorded at net book value, and the joint venture is included in the Company’s consolidated financial statements contained herein. The joint venture partner’s ownership interest in the joint venture is accounted for as noncontrolling interest. For further discussion refer to Note 9 . The difference between the joint venture partner’s cash contribution and its proportional share of the net book value of the properties was recorded in additional paid in capital in the Company’s consolidated balance sheets and consolidated statement of changes in equity.

Investments in Owned Properties

Investments in Owned Properties	9 Months Ended
	Sep. 30, 2018
Owned properties
Real Estate Properties [Line Items]
Investments in Owned Properties	Investments in Owned Properties Owned properties, both wholly-owned and those owned through investments in VIEs, consisted of the following: September 30, 2018 December 31, 2017 Land (1) $ 653,431 $ 646,991 Buildings and improvements 6,478,611 6,096,527 Furniture, fixtures and equipment 380,593 348,828 Construction in progress 191,879 393,045 7,704,514 7,485,391 Less accumulated depreciation (1,182,809 ) (1,035,027 ) Owned properties, net $ 6,521,705 $ 6,450,364 (1) The land balance above includes undeveloped land parcels with book values of approximately $ 54.4 million and $38.0 million as of September 30, 2018 and as of December 31, 2017 , respectively. It also includes land totaling approximately $10.3 million and $29.9 million as of September 30, 2018 and December 31, 2017 , respectively, related to properties under development.

On-Campus Participating Propert

On-Campus Participating Properties	9 Months Ended
	Sep. 30, 2018
On-campus participating properties
Real Estate Properties [Line Items]
On-Campus Participating Properties	On-Campus Participating Properties On-campus participating properties are as follows: Historical Cost Lessor/University Lease Commencement Required Debt September 30, 2018 December 31, 2017 Texas A&M University System / Prairie View A&M University (1) 2/1/1996 9/1/2023 $ 45,446 $ 44,364 Texas A&M University System / Texas A&M International 2/1/1996 9/1/2023 7,077 6,923 Texas A&M University System / Prairie View A&M University (2) 10/1/1999 8/31/2025 28,758 27,802 8/31/2028 University of Houston System / University of Houston (3) 9/27/2000 8/31/2035 36,344 36,062 West Virginia University System / West Virginia University 7/16/2013 7/16/2045 45,289 44,845 162,914 159,996 Accumulated amortization (84,048 ) (78,192 ) On-campus participating properties, net $ 78,866 $ 81,804 (1) Consists of three phases placed in service between 1996 and 1998. (2) Consists of two phases placed in service in 2000 and 2003. (3) Consists of two phases placed in service in 2001 and 2005.

Debt

Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	Debt A summary of the Company’s outstanding consolidated indebtedness, including unamortized debt premiums and discounts, is as follows: September 30, 2018 December 31, 2017 Debt secured by owned properties: Mortgage loans payable: Unpaid principal balance $ 765,922 $ 496,557 Unamortized deferred financing costs (2,017 ) (2,144 ) Unamortized debt premiums 12,813 19,006 776,718 513,419 Construction loans payable (1) 49,511 51,780 Unamortized deferred financing costs (697 ) (888 ) 825,532 564,311 Debt secured by on-campus participating properties: Mortgage loans payable (2) 68,337 69,776 Bonds payable 27,030 30,575 Unamortized deferred financing costs (554 ) (642 ) 94,813 99,709 Total secured mortgage, construction and bond debt 920,345 664,020 Unsecured notes, net of unamortized OID and deferred financing costs (3) 1,587,796 1,585,855 Unsecured term loans, net of unamortized deferred financing costs (4) 198,681 647,044 Unsecured revolving credit facility 266,900 127,600 Total debt, net $ 2,973,722 $ 3,024,519 (1) Construction loans payable relates to construction loans partially financing the development of two presale development projects. These properties are owned by entities determined to be VIEs for which the Company is the primary beneficiary. The creditors of these construction loans do not have recourse to the assets of the Company. (2) The creditors of mortgage loans payable related to on-campus participating properties do not have recourse to the assets of the Company. (3) Includes net unamortized original issue discount (“OID”) of $1.7 million and $1.9 million at September 30, 2018 and December 31, 2017 , respectively, and net unamortized deferred financing costs of $10.5 million and $12.2 million at September 30, 2018 and December 31, 2017 , respectively. (4) Includes net unamortized deferred financing costs of $1.3 million and $3.0 million at September 30, 2018 and December 31, 2017 , respectively. Mortgage and Construction Loans Payable During the nine months ended September 30, 2018 , the Company paid off approximately $55.9 million of fixed rate mortgage debt secured by three owned properties. Additionally, during the nine months ended September 30, 2018 , the Company paid $2.7 million in debt defeasance costs associated with the early pay-off of mortgage loans in connection with the sale of one owned property and one owned property included in the ACC / Allianz Joint Venture Transaction (see Note 4 ). These costs were partially offset by the net write-off of $1.9 million of premiums and deferred financing costs, resulting in a loss from early extinguishment of debt of $0.8 million . During the nine months ended September 30, 2017 , the Company paid off approximately $30.5 million off any fixed rate mortgage debt secured by one wholly-owned property. In the third quarter of 2018, one of the joint ventures that is part of the Core Transaction paid off approximately $71.0 million of construction debt with proceeds from an additional investment made by the Company to the joint venture (see Note 3 ). Additionally, in August 2018, upon completion of construction, the Company acquired The Edge - Stadium Centre, a property subject to a presale agreement. Approximately $19.3 million of construction debt used to partially finance the development of the presale project was paid off upon acquisition. In May 2018, as part of the ACC / Allianz Joint Venture Transaction, the joint venture issued $330.0 million of fixed rate secured mortgage debt with a coupon of 4.07% and the full amount of principal due at maturity in June 2028 (see Note 4 ). In May 2017, the lender of the non-recourse mortgage loan secured by Blanton Common, a property located near Valdosta State University which was inherited as part of the GMH student housing transaction in 2008, sent a formal notice of default and initiated foreclosure proceedings. The property generated insufficient cash flow to cover the debt service on the mortgage, which had a balance of $27.4 million at default and a contractual maturity date of August 2017. In May 2017, the lender began receiving the net operating cash flows of the property each month in lieu of scheduled monthly mortgage payments. In June 2017, the Company recorded an impairment charge for this property of $15.3 million . In August 2017, the property transferred to receivership and a third-party manager began managing the property on behalf of the lender. As of September 30, 2018 , the Company was cooperating with the lender to allow for a consensual foreclosure process upon which the property will be surrendered to the lender in satisfaction of the mortgage loan. Unsecured Notes The Company has issued the following senior unsecured notes: Date Issued Amount % of Par Value Coupon Yield Original Issue Discount Term (Years) April 2013 $ 400,000 99.659 3.750 % 3.791 % $ 1,364 10 June 2014 400,000 99.861 4.125 % 4.269 % (1) 556 10 September 2015 400,000 99.811 3.350 % 3.391 % 756 5 October 2017 400,000 99.912 3.625 % 3.635 % 352 10 $ 1,600,000 $ 3,028 (1) The yield includes the effect of the amortization of interest rate swap terminations (see Note 11 ). The notes are fully and unconditionally guaranteed by the Company. Interest on the notes is payable semi-annually. The terms of the unsecured notes include certain financial covenants that require the Operating Partnership to limit the amount of total debt and secured debt as a percentage of total asset value, as defined. In addition, the Operating Partnership must maintain a minimum ratio of unencumbered asset value to unsecured debt, as well as a minimum interest coverage level. As of September 30, 2018 , the Company was in compliance with all such covenants. Unsecured Revolving Credit Facility The Company has a $700 million unsecured revolving credit facility, which may be expanded by up to an additional $500 million upon the satisfaction of certain conditions. The maturity date of the revolving credit facility is in March 2022. The unsecured revolving credit facility bears interest at a variable rate, at the Company’s option, based upon a base rate of one-, two-, three- or six-month LIBOR, plus, in each case, a spread based upon the Company’s investment grade rating from either Moody’s Investor Services, Inc. or Standard & Poor’s Rating Group. Additionally, the Company is required to pay a facility fee of 0.20% per annum on the $700 million revolving credit facility. As of September 30, 2018 , the revolving credit facility bore interest at a weighted average annual rate of 3.39% ( 2.19% + 1.00% spread + 0.20% facility fee), and availability under the revolving credit facility totaled $433.1 million . The terms of the unsecured credit facility include certain restrictions and covenants, which limit, among other items, the incurrence of additional indebtedness and liens. The facility contains customary affirmative and negative covenants and also contains financial covenants that, among other things, require the Company to maintain certain maximum leverage ratios and minimum ratios of “EBITDA” (earnings before interest, taxes, depreciation and amortization) to fixed charges. The financial covenants also include a minimum asset value requirement, a maximum secured debt ratio, and a minimum unsecured debt service coverage ratio. As of September 30, 2018 , the Company was in compliance with all such covenants. Unsecured Term Loans In May 2018, the Company repaid the $300 million unsecured term loan (“Term Loan III Facility”) and the $150 million unsecured term loan (“Term Loan I Facility”) which were due to mature in September 2018 and March 2021, respectively, using the proceeds from the sale of a partial interest in a portfolio of seven owned properties and the portfolio sale of three owned properties (see Note 4 ). In connection with the pay-off of the Term Loan III Facility and Term Loan I Facility, the Company accelerated the amortization of $0.9 million of deferred financing costs. In 2017, the Company entered into an Unsecured Term Loan Credit Agreement (the “Term Loan II Facility”) totaling $200 million . The maturity date of the Term Loan II Facility is June 2022. The agreement has an accordion feature that allows the Company to expand the amount by up to an additional $100 million , subject to the satisfaction of certain conditions. The weighted average annual rate on the Term Loan II Facility was 3.20% ( 2.10% + 1.10% spread), at September 30, 2018 . The terms of the term loan facilities described above include certain restrictions and covenants consistent with those of the unsecured revolving credit facility discussed above. As of September 30, 2018 , the Company was in compliance with all such covenants.

Stockholders' Equity _ Partners

Stockholders' Equity / Partners' Capital	9 Months Ended
	Sep. 30, 2018
Stockholders' Equity Note [Abstract]
Stockholders' Equity / Partners' Capital	Stockholders’ Equity / Partners’ Capital Stockholders’ Equity - Company In May 2018, the Company renewed its at-the-market share offering program (the “ATM Equity Program”) through which the Company may issue and sell, from time to time, shares of common stock having an aggregate offering price of up to $500 million . The shares that may be sold under this program include shares of common stock of the Company with an aggregate offering price of approximately $233.0 million that were not sold under the Company's previous ATM equity program that expired in May 2018. Actual sales under the program will depend on a variety of factors, including, but not limited to, market conditions, the trading price of the Company’s common stock and determinations of the appropriate sources of funding for the Company. There was no activity under the Company’s ATM Equity Program during the three and nine months ended September 30, 2018 . The following table presents activity under the Company’s previous ATM equity program during the three and nine months ended September 30, 2017 : Three Months Ended Nine Months Ended Total net proceeds $ 1,135 $ 188,538 Commissions paid to sales agents $ 14 $ 2,374 Weighted average price per share $ 48.09 $ 48.34 Shares of common stock sold 23,900 3,949,356 As of September 30, 2018 , the Company had approximately $500.0 million available for issuance under its ATM Equity Program. In 2015, the Company established a Non-Qualified Deferred Compensation Plan (“Deferred Compensation Plan”) maintained for the benefit of certain employees and members of the Company’s Board of Directors, in which vested share awards (see Note 10 ), salary and other cash amounts earned may be deposited. Deferred Compensation Plan assets are held in a rabbi trust, which is subject to the claims of the Company’s creditors in the event of bankruptcy or insolvency. The shares held in the Deferred Compensation Plan are classified within stockholders’ equity in a manner similar to the manner in which treasury stock is classified. Subsequent changes in the fair value of the shares are not recognized. During the nine months ended September 30, 2018 , 12,956 and 7,131 shares of vested stock were deposited into and withdrawn from the Deferred Compensation Plan, respectively. As of September 30, 2018 , 69,603 shares of ACC’s common stock were held in the Deferred Compensation Plan. Partners’ Capital – Operating Partnership In connection with the issuance of common shares under the ATM Equity Program discussed above, ACCOP issued a number of Common OP Units to ACC equivalent to the number of common shares issued by ACC.

Noncontrolling Interests

Noncontrolling Interests	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Noncontrolling Interests Interests in Consolidated Real Estate Joint Ventures and Presale Arrangements Noncontrolling interests - partially owned properties: As of September 30, 2018 , the Operating Partnership consolidates four joint ventures that own and operate ten owned off-campus properties, including the ACC / Allianz Joint Venture Transaction discussed in Note 4 . Additionally, the Company has entered into two presale agreements to purchase two in-process development properties. The portion of net assets attributable to the third-party partners in these arrangements is classified as “noncontrolling interests - partially owned properties” within equity and capital on the accompanying consolidated balance sheets of ACC and the Operating Partnership, respectively. Redeemable noncontrolling interests (ACC) / redeemable limited partners (Operating Partnership) : As part of the Core Transaction discussed in detail in Note 3 , the Company entered into two joint ventures (the “Core Joint Ventures”) in the third quarter of 2017. The Company is consolidating these joint ventures and the noncontrolling interest holder in each of these consolidated joint ventures has the option to redeem its noncontrolling interest in the entities through the exercise of put options. The options will be exercisable in the third and fourth quarter of 2019, and the redemption price is based on the fair value of the properties at the time of option exercise. As the exercise of the options is outside of the Company’s control, the portion of net assets attributable to the third-party partner in each of the Core Joint Ventures is classified as “redeemable noncontrolling interests” and “redeemable limited partners” in the mezzanine section of the accompanying consolidated balance sheets of ACC and the Operating Partnership, respectively. During the nine months ended September 30, 2018 , the redemption value of redeemable noncontrolling interest increased by $68.7 million due to a change in the fair value of the net assets held by the joint ventures that are part of the Core Transaction primarily as a result of the underlying properties becoming operational during the third quarter and the leasing results for the 2018-2019 academic year. The corresponding offset for the adjustment to the redemption value is recorded in additional paid in capital. The Company’s fair value analysis of the properties incorporates information obtained from a number of sources, including the Company’s analysis of comparable properties in the Company’s portfolio, estimations of net operating results of the properties, capitalization rates, discount rates, and other market data. As the change in redemption value is based on fair value, there is no effect on the Company’s earnings per share. The third-party partners’ share of the income or loss of the joint ventures described above is calculated based on the partners’ economic interest in the joint ventures and is included in “net income attributable to noncontrolling interests” on the consolidated statements of comprehensive income of ACC, and is reported as “net income attributable to noncontrolling interests - partially owned properties” on the consolidated statements of comprehensive income of the Operating Partnership. Operating Partnership Ownership Also included in redeemable noncontrolling interests (ACC) / redeemable limited partners (Operating Partnership) are OP Units for which the Operating Partnership is required, either by contract or securities law, to deliver registered common shares of ACC to the exchanging OP unit holder, or for which the Operating Partnership has the intent or history of exchanging such units for cash. The units classified as such include Series A Preferred Units (“Preferred OP Units”) as well as Common OP Units. The value of redeemable noncontrolling interests (ACC) / redeemable limited partners (Operating Partnership) related to OP Units on the accompanying consolidated balance sheets is reported at the greater of fair value, which is based on the closing market value of the Company’s common stock at period end, or historical cost at the end of each reporting period. The OP Unitholders’ share of the income or loss of the Company is included in “net income attributable to noncontrolling interests” on the consolidated statements of comprehensive income of ACC. As of September 30, 2018 and December 31, 2017 , respectively, approximately 0.5% and 0.8% of the equity interests of the Operating Partnership were held by owners of Common OP Units and Preferred OP Units not held by ACC or ACC Holdings. During the nine months ended September 30, 2018 , 412,343 Common OP Units were converted into an equal number of shares of ACC’s common stock. During the year ended December 31, 2017 , 22,000 Common OP Units were converted into an equal number of shares of ACC’s common stock. Below is a table summarizing the activity of redeemable noncontrolling interests (ACC) / redeemable limited partners (Operating Partnership) for the nine months ended September 30, 2018 , which includes both the redeemable joint venture partners and OP Units discussed above: Balance, December 31, 2017 $ 132,169 Net income 554 Distributions (1,213 ) Conversion of OP Units into shares of ACC common stock (13,333 ) Contributions from noncontrolling interests 620 Adjustments to reflect OP Units at fair value 65,857 Balance, September 30, 2018 $ 184,654

Incentive Award Plan

Incentive Award Plan	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Incentive Award Plan	Incentive Award Plan In May 2018, the Company’s stockholders approved the American Campus Communities, Inc. 2018 Incentive Award Plan (the “2018 Plan”). The 2018 Plan replaced the Company’s 2010 Incentive Award Plan (the “2010 Plan”). The 2018 Plan provides for the grant of various stock-based incentive awards to selected employees and directors of the Company and the Company’s affiliates. The types of awards that may be granted under the 2018 Plan include incentive stock options, nonqualified stock options, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), profits interest units (“PIUs”) and other stock-based awards. The Company has reserved a total 3.5 million shares of the Company’s common stock for issuance pursuant to the 2018 Plan, subject to certain adjustments for changes in the Company’s capital structure, as defined in the 2018 Plan. Upon approval of the 2018 Plan, all remaining authorized shares that were not granted under the 2010 Plan were forfeited and are no longer available for issuance as new awards. Restricted Stock Units (“RSUs”) In March and September 2018, the Company appointed two new members to the Board of Directors who were granted RSUs valued at $115,000 each. A compensation charge of approximately $0.2 million was recorded during the nine months ended September 30, 2018 related to these awards. Upon reelection to the Board of Directors in May 2018 , all members of the Company’s Board of Directors were granted RSUs in accordance with the 2018 Plan. These RSUs were valued at $160,000 for the Chairman of the Board of Directors and at $115,000 for all other members. The number of RSUs was determined based on the fair market value of the Company’s stock on the date of grant, as defined in the 2018 Plan. All awards vested and settled immediately on the date of grant, and the Company delivered shares of common stock, as determined by the Compensation Committee of the Board of Directors. A compensation charge of approximately $0.9 million was recorded during the nine months ended September 30, 2018 related to these awards. A summary of RSUs as of September 30, 2018 and activity during the nine months then ended is presented below: Number of RSUs Outstanding at December 31, 2017 — Granted 27,376 Settled in common shares (27,376 ) Outstanding at September 30, 2018 — Restricted Stock Awards (“RSAs”) A summary of RSAs as of September 30, 2018 and activity during the nine months then ended is presented below: Number of RSAs Nonvested balance at December 31, 2017 810,870 Granted 357,387 Vested (1) (240,845 ) Forfeited (48,198 ) Nonvested balance at September 30, 2018 879,214 (1) Includes shares withheld to satisfy tax obligations upon vesting. The fair value of RSAs is calculated based on the closing market value of ACC’s common stock on the date of grant. The fair value of these awards is amortized to expense over the vesting periods. Amortization expense for the three months ended September 30, 2018 and 2017 amounted to approximately $2.7 million and $2.4 million , respectively, and $8.8 million and $10.6 million for the nine months ended September 30, 2018 and 2017 , respectively. The amortization of restricted stock awards for the nine months ended September 30, 2017 includes $2.4 million of contractual executive separation and retirement charges incurred with regard to the retirement of the Company’s former Chief Financial Officer, representing the June 30, 2017 vesting of 46,976 RSAs, net of shares withheld for taxes, related to the retirement.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and the use of derivative financial instruments. Specifically, the Company enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and forward starting swaps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Forward starting swaps are used to protect the Company against adverse fluctuations in interest rates by reducing its exposure to variability in cash flows relating to interest payments on a forecasted issuance of debt. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in other comprehensive income (outside of earnings) and subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The ineffective portion of changes in the fair value of the derivative is recognized directly in earnings. Ineffectiveness resulting from the derivative instruments was immaterial for both the three and nine month periods ended September 30, 2018 and 2017 . As of September 30, 2018 , the Company had outstanding interest rate swap contracts with a notional amount of approximately $96.7 million . The fair value of such interest rate swap contracts was immaterial as of both September 30, 2018 and December 31, 2017 .

Fair Value Disclosures

Fair Value Disclosures	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Disclosures Financial Instruments Carried at Fair Value The following table presents information about the Company’s financial instruments measured at fair value on a recurring basis as of September 30, 2018 and 2017 , and indicates the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair value. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities the Company has the ability to access. Fair values determined by Level 2 inputs utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets and inputs other than quoted prices observable for the asset or liability, such as interest rates and yield curves observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In instances in which the inputs used to measure fair value may fall into different levels of the fair value hierarchy, the level in the fair value hierarchy within which the fair value measurement in its entirety has been determined is based on the lowest level input significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. Disclosures concerning financial instruments measured at fair value are as follows: Fair Value Measurements as of September 30, 2018 December 31, 2017 Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mezzanine: Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership) $ — $ 27,672 $ 156,982 $ 184,654 $ — $ 44,503 $ 87,666 $ 132,169 The OP Unit component of redeemable noncontrolling interests has a redemption feature, and is marked to its redemption value when the redemption value exceeds the original issue price. The redemption value is based on the fair value of the Company’s common stock at the redemption date, and therefore, is calculated based on the fair value of the Company’s common stock at the balance sheet date. Since the valuation is based on observable inputs such as quoted prices for similar instruments in active markets, these instruments are classified in Level 2 of the fair value hierarchy. As discussed in Note 9 , the redeemable noncontrolling interests related to the joint venture partners in the Core Transaction are marked to their redemption value at each balance sheet date. The redemption value is based on the fair value of the underlying properties held by the joint ventures. This analysis incorporates information obtained from a number of sources, including the Company’s analysis of comparable properties in the Company’s portfolio, estimations of net operating results of the properties, capitalization rates, discount rates, and other market data. The Company has determined these estimates are primarily based upon unobservable inputs and therefore are considered to be Level 3 inputs within the fair value hierarchy. Financial Instruments Not Carried at Fair Value Cash and Cash Equivalents, Restricted Cash, Student Contracts Receivable, Other Assets, Accounts Payable and Accrued Expenses and Other Liabilities: The Company estimates that the carrying amount approximates fair value, due to the short maturity of these instruments. Loans Receivable : The fair value of loans receivable is based on a discounted cash flow analysis consisting of scheduled cash flows and discount rate estimates to approximate those that a willing buyer and seller might use. These financial instruments utilize Level 3 inputs. Mortgage Loans Payable : The fair value of mortgage loans payable is based on the present value of the cash flows at current market interest rates through maturity. The Company has concluded the fair value of these financial instruments utilize Level 2 inputs as the majority of the inputs used to value these instruments fall within Level 2 of the fair value hierarchy. Bonds Payable : The fair value of bonds payable is based on quoted prices in markets that are not active due to the unique characteristics of these financial instruments; as such, the Company has concluded the inputs used to measure fair value fall within Level 2 of the fair value hierarchy. Unsecured Notes : In calculating the fair value of unsecured notes, interest rate and spread assumptions reflect current creditworthiness and market conditions available for the issuance of unsecured notes with similar terms and remaining maturities. These financial instruments utilize Level 2 inputs. Construction Loans Payable, Unsecured Revolving Credit Facility, and Unsecured Term Loans : The fair value of these instruments approximates their carrying values due to the variable interest rate feature of these instruments. The table below contains the estimated fair value and related carrying amounts for the Company’s financial instruments as of September 30, 2018 and December 31, 2017 : September 30, 2018 December 31, 2017 Estimated Fair Value Carrying Amount Estimated Fair Value Carrying Amount Assets: Loans receivable $ 54,140 $ 60,424 $ 54,140 $ 57,948 Liabilities: Unsecured notes $ 1,554,144 $ 1,587,796 (1) $ 1,620,839 $ 1,585,855 (1) Mortgage loans payable (4) $ 768,542 $ 803,389 (2) $ 571,676 $ 582,927 (2) Bonds payable $ 28,544 $ 26,720 (3) $ 32,552 $ 30,201 (3) (1) Includes net unamortized OID and net unamortized deferred financing costs (see Note 7 ). (2) Includes net unamortized debt premiums and discounts and net unamortized deferred financing costs (see Note 7 ). (3) Includes net unamortized deferred financing costs (see Note 7 ). (4) In July 2018, the fixed feature of a mortgage loan secured by an on-campus participating property expired, and the mortgage loan became classified as variable rate debt.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments Construction Contracts: As of September 30, 2018 , excluding two properties under construction and subject to presale arrangements which are being funded by construction loans, the Company estimates additional costs to complete three owned development projects under construction to be approximately $132.9 million . Joint Ventures: As part of the Core Transaction, the Company entered into two joint ventures during the third quarter of 2017. As part of this transaction, the Company is obligated to increase its investment in the joint ventures over a two year period. As of September 30, 2018 , the remaining funding commitment was approximately $200.9 million . Of this amount, $46.9 million was paid in the fourth quarter 2018, with the remainder anticipated to be paid in September and October 2019. See Note 3 for further discussion. Presale Development Projects: The Company has entered into two presale agreements to purchase properties which will be completed in Fall 2019. Total estimated development costs of approximately $107.3 million include the purchase price and elected upgrades, of which $90.0 million remains to be funded as of September 30, 2018 . The Company is obligated to purchase the properties as long as the developer meets certain construction completion deadlines and other closing conditions. The Company is responsible for leasing, management, and initial operations of the project while the third-party developer retains development risk during the construction period. See Note 9 for further discussion. The Company expects to fund the commitments mentioned above through a combination of proceeds from cash flows generated from operations, anticipated property dispositions, joint venture activity, and a combination of debt and equity transactions, which may include net proceeds from the ATM Equity Program discussed in Note 8 , borrowings under the Company’s existing unsecured credit facilities, and accessing the unsecured bond market. Development-related Guarantees: For certain of its third-party development projects, the Company commonly provides alternate housing and project cost guarantees, subject to force majeure. These guarantees are typically limited, on an aggregate basis, to the amount of the projects’ related development fees or a contractually agreed-upon maximum exposure amount. Alternate housing guarantees generally require the Company to provide substitute living quarters and transportation for students to and from the university if the project is not complete by an agreed-upon completion date. These guarantees typically expire at the later of five days after completion of the project or once the Company has moved all students from the substitute living quarters into the project. Under project cost guarantees, the Company is responsible for the construction cost of a project in excess of an approved budget. The budget consists primarily of costs included in the general contractors’ guaranteed maximum price contract (“GMP”). In most cases, the GMP obligates the general contractor, subject to force majeure and approved change orders, to provide completion date guarantees and to cover cost overruns and liquidated damages. In addition, the GMP is in certain cases secured with payment and performance bonds. Project cost guarantees expire upon completion of certain developer obligations, which are normally satisfied within one year after completion of the project. The Company’s estimated maximum exposure amount under the above guarantees is approximately $10.3 million as of September 30, 2018 . As of September 30, 2018 , management did not anticipate any material deviations from schedule or budget related to third-party development projects currently in progress. In the normal course of business, the Company enters into various development-related purchase commitments with parties that provide development-related goods and services. In the event that the Company was to terminate development services prior to the completion of projects under construction, the Company could potentially be committed to satisfy outstanding purchase orders with such parties. Conveyance to University: In August 2013, the Company entered into an agreement to convey fee interest in a parcel of land, on which one of the Company’s student housing properties resides (University Crossings), to Drexel University (the “University”). Concurrent with the land conveyance, the Company as lessee entered into a ground lease agreement with the University as lessor for an initial term of 40 years , with three 10 -year extensions, at the Company’s option. The Company also agreed to convey the building and improvements to the University at an undetermined date in the future and to pay real estate transfer taxes not to exceed $2.4 million . The Company paid approximately $0.6 million in real estate transfer taxes upon the conveyance of land to the University, leaving approximately $1.8 million to be paid by the Company upon the transfer of the building and improvements. Other Guarantees: In 2017, as part of the purchase of an undeveloped land parcel, the Company entered into an agreement to construct a commercial retail space within a future development that will be conveyed back to the seller upon construction completion. If the construction of the retail space is not completed in accordance with the agreement, the Company is required to pay liquidated damages of $2.1 million . As of September 30, 2018 , management anticipates completing construction of the retail space in accordance with the agreement. Contingencies Litigation: The Company is subject to various claims, lawsuits and legal proceedings, as well as other matters that have not been fully resolved and that have arisen in the ordinary course of business. While it is not possible to ascertain the ultimate outcome of such matters, management believes that the aggregate amount of such liabilities, if any, in excess of amounts provided or covered by insurance, will not have a material adverse effect on the consolidated financial position or results of operations of the Company. However, the outcome of claims, lawsuits and legal proceedings brought against the Company is subject to significant uncertainty. Therefore, although management considers the likelihood of such an outcome to be remote, the ultimate results of these matters cannot be predicted with certainty. Letters of Intent: In the ordinary course of the Company’s business, the Company enters into letters of intent indicating a willingness to negotiate for acquisitions, dispositions or joint ventures. Such letters of intent are non-binding (except with regard to exclusivity and confidentiality), and neither party to the letter of intent is obligated to pursue negotiations unless and until a definitive contract is entered into by the parties. Even if definitive contracts are entered into, the letters of intent relating to the acquisition and disposition of real property and resulting contracts generally contemplate that such contracts will provide the acquirer with time to evaluate the property and conduct due diligence, during which periods the acquirer will have the ability to terminate the contracts without penalty or forfeiture of any material deposit or earnest money. There can be no assurance that definitive contracts will be entered into with respect to any matter covered by letters of intent or that the Company will consummate any transaction contemplated by any definitive contract. Furthermore, due diligence periods for real property are frequently extended as needed. Once the due diligence period expires, the Company is then at risk under a real property acquisition contract, but only to the extent of any non-refundable earnest money deposits associated with the contract and subject to normal closing conditions being met. Environmental Matters: The Company is not aware of any environmental liability with respect to the properties that would have a material adverse effect on the Company’s business, assets or results of operations. However, there can be no assurance that such a material environmental liability does not exist. The existence of any such material environmental liability could have an adverse effect on the Company’s results of operations and cash flows.

Segments

Segments	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segments	Segments The Company defines business segments by their distinct customer base and service provided. The Company has identified four reportable segments: Owned Properties, On-Campus Participating Properties, Development Services, and Property Management Services. Management evaluates each segment’s performance based on operating income before depreciation, amortization and minority interests. During the year ended December 31, 2017 , the Company revised the measure of profit or loss for each segment to include the allocation of costs related to corporate management and oversight and to exclude intercompany management fee revenue. This was due to a presentation change in the information used by the Company’s chief operating decision makers to assess segment and company-wide performance and allocate resources, which was driven by the reorganization of duties within the Company’s executive management team. Prior period amounts have been reclassified to conform to the current period presentation. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Owned Properties Rental revenues and other income $ 203,526 $ 184,282 $ 600,138 $ 533,866 Interest income 382 385 1,146 1,161 Total revenues from external customers 203,908 184,667 601,284 535,027 Operating expenses before depreciation, amortization, and ground/facility lease expense (107,997 ) (99,423 ) (282,193 ) (249,552 ) Ground/facility lease expense (2,306 ) (1,877 ) (6,293 ) (5,163 ) Interest expense, net (1) (5,622 ) (1,540 ) (9,011 ) (1,194 ) Operating income before depreciation and amortization $ 87,983 $ 81,827 $ 303,787 $ 279,118 Depreciation and amortization $ 62,909 $ 58,339 $ 185,171 $ 161,341 Capital expenditures $ 144,910 $ 196,910 $ 428,065 $ 473,638 On-Campus Participating Properties Rental revenues and other income $ 6,980 $ 6,799 $ 23,605 $ 23,128 Interest income 43 24 105 47 Total revenues from external customers 7,023 6,823 23,710 23,175 Operating expenses before depreciation, amortization, and ground/facility lease expense (3,875 ) (3,923 ) (11,030 ) (11,080 ) Ground/facility lease expense (645 ) (452 ) (2,233 ) (1,988 ) Interest expense (1,282 ) (1,312 ) (3,804 ) (3,987 ) Operating income before depreciation and amortization $ 1,221 $ 1,136 $ 6,643 $ 6,120 Depreciation and amortization $ 1,962 $ 1,892 $ 5,856 $ 5,621 Capital expenditures $ 1,394 $ 2,039 $ 2,918 $ 2,909 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Development Services Development and construction management fees $ 835 $ 3,566 $ 3,883 $ 4,697 Operating expenses (2,056 ) (2,114 ) (5,976 ) (5,971 ) Operating (loss) income before depreciation and amortization $ (1,221 ) $ 1,452 $ (2,093 ) $ (1,274 ) Property Management Services Property management fees from external customers $ 2,128 $ 2,291 $ 7,311 $ 7,193 Operating expenses (1,775 ) (1,765 ) (5,597 ) (5,818 ) Operating income before depreciation and amortization $ 353 $ 526 $ 1,714 $ 1,375 Reconciliations Total segment revenues and other income $ 213,894 $ 197,347 $ 636,188 $ 570,092 Unallocated interest income earned on investments and corporate cash 849 850 2,489 2,515 Total consolidated revenues, including interest income $ 214,743 $ 198,197 $ 638,677 $ 572,607 Segment operating income before depreciation and amortization $ 88,336 $ 84,941 $ 310,051 $ 285,339 Depreciation and amortization (67,247 ) (62,271 ) (199,191 ) (172,588 ) Net unallocated expenses relating to corporate interest and overhead (24,615 ) (23,636 ) (83,958 ) (65,448 ) Gain (loss) from disposition of real estate — — 42,314 (632 ) Other operating and nonoperating income 570 — 3,218 — Loss from early extinguishment of debt — — (784 ) — Provision for real estate impairment — — — (15,317 ) Income tax provision 219 (267 ) (2,147 ) (791 ) Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 (1) Net of capitalized interest and amortization of debt premiums.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Distributions : On October 31, 2018 , the Board of Directors of the Company declared a distribution per share of $0.46 , which will be paid on November 26, 2018 to all common stockholders of record as of November 12, 2018 . At the same time, the Operating Partnership will pay an equivalent amount per unit to holders of Common OP Units, as well as the quarterly cumulative preferential distribution to holders of Preferred OP Units (see Note 9 ). In October 2018, the Company increased its investment in a joint venture that is part of the Core Transaction by $46.9 million (See Notes 3 and 13), and the joint venture paid off approximately $40.2 million of construction debt with proceeds from the investment.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation and use of Estimates	Basis of Presentation and use of Estimates The accompanying consolidated financial statements, presented in U.S. dollars, are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the date of the financial statements, and revenue and expenses during the reporting periods. The Company’s actual results could differ from those estimates and assumptions. All material intercompany transactions among consolidated entities have been eliminated. All dollar amounts in the tables herein, except share, per share, unit and per unit amounts, are stated in thousands unless otherwise indicated.
Principles of Consolidation	Principles of Consolidation The Company’s consolidated financial statements include its accounts and the accounts of other subsidiaries and joint ventures (including partnerships and limited liability companies) over which it has control. Investments acquired or created are evaluated based on the accounting guidance relating to variable interest entities (“VIEs”), which requires the consolidation of VIEs in which the Company is considered to be the primary beneficiary. If the investment is determined not to be a VIE, then the investment is evaluated for consolidation using the voting interest model.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2016-02 (“ASU 2016-02”), “Leases (Topic 842): Amendments to the FASB Accounting Standards Codification.” ASU 2016-02 outlines principles for the recognition, measurement, presentation and disclosure of leases. Subsequent to the issuance of ASU 2016-02, the FASB issued additional ASUs clarifying aspects of the new lease accounting standard, which will be effective upon adoption of ASU 2016-02. The Company plans to adopt ASU 2016-02 as of January 1, 2019, utilizing the “modified retrospective” method. While the Company is still completing its evaluation of the effect that the new standard will have on its consolidated financial statements and related disclosures, the anticipated impact of ASU 2016-02 is as follows: As Lessee: • Under the new standard, lessees will classify leases as either operating or finance leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized on a straight-line basis over the term of the lease (operating lease) or on an effective interest method (finance lease). In addition, ASU 2016-02 requires lessees to recognize right-of-use assets and related lease liabilities for leases with a term greater than 12 months regardless of their lease classification. As of September 30, 2018, the Company is a lessee under 24 ground leases and 2 corporate office headquarters leases for which it will recognize a right of use asset and lease liability upon adoption. We are currently determining the appropriate discount rate to utilize in our calculations of the right-of-use asset and lease liability, and, as such, we have not finalized our calculations as of September 30, 2018. Details of the future minimum lease payments for leases in existence as of December 31, 2017 are disclosed in Note 15 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2017. • Because the Company’s existing leases under which it is a lessee will continue to be classified as operating leases, the timing and pattern of lease expense recognition (straight-line basis) will remain unchanged. However, for any leases entered into or modified after the adoption date, the leases will need to be evaluated under the new standard and may be classified as finance leases depending on the terms of the transactions. As Lessor: • Under the new standard, the accounting for lessors will remain largely unchanged from current GAAP; however, ASU 2016-02 requires that lessors expense, on an as-incurred basis, certain initial direct costs that are not incremental in negotiating a lease. Under existing standards, these costs are capitalizable and therefore the new lease standard will result in certain of these costs being expensed as incurred after adoption. For the Company, these costs include internal leasing payroll costs incurred for owned and presale development projects, as well as legal expenses incurred when negotiating commercial leases. • The new standard provides a practical expedient that allows lessors to not separate certain lease and non-lease components if certain criteria are met. For the Company’s commercial leases under which the tenants pay for common area maintenance charges, the Company assessed the criteria and determined that the timing and pattern of transfer for common area maintenance and the related rental revenue is the same. Therefore, the Company plans to elect the practical expedient which will result in no change to how revenue from commercial leases is currently recorded. The Company expects to adopt the following additional practical expedients available for implementation: • An entity need not reassess whether any existing or expired contracts are or contain leases; • An entity need not reassess lease classification for any existing or expired leases; • An entity need not reassess initial direct costs for any existing leases; and • Permitted use of hindsight in determining the lease term and in assessing impairment of right of use assets. In addition, the Company does not expect the following accounting pronouncements to have a material effect on its consolidated financial statements: Accounting Standards Update Effective Date ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract” January 1, 2020 ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” January 1, 2020 ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” January 1, 2019 ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” January 1, 2019 ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” January 1, 2020 Recently Adopted Accounting Pronouncements Accounting Standards Update 2016-18 (“ASU 2016-18”), “Statement of Cash Flows: Restricted Cash” On January 1, 2018, the Company adopted ASU 2016-18. The amendments in this update require the change in restricted cash to be reported with cash and cash equivalents when reconciling between beginning and ending amounts in the statements of cash flows. The Company applied the amendments retrospectively to each period presented in the consolidated statements of cash flows of the Company. Prior to the adoption of ASU 2016-18, the Company reported the change in restricted cash within operating, investing, and financing activities in its consolidated statement of cash flows. As a result of the Company’s adoption of this standard and the retrospective application, cash and cash equivalents in the consolidated statements of cash flows as of September 30, 2017 increased by approximately $25.8 million to reflect the inclusion of the restricted cash balance at the end of the period, net cash provided by operating activities for the nine months ended September 30, 2017 increased by approximately $0.6 million , net cash used in investing activities decreased by approximately $1.3 million , and net cash provided by financing activities decreased by approximately $0.9 million . Accounting Standards Update 2014-09 (“ASU 2014-09”), “Revenue From Contracts With Customers (Topic 606)” On January 1, 2018, the Company adopted ASU 2014-09 and all related clarifying Accounting Standards Updates associated with ASU 2014-09. ASU 2014-09 provides a single comprehensive revenue recognition model for contracts with customers (excluding certain contracts, such as lease contracts) to improve comparability within industries. ASU 2014-09 requires an entity to recognize revenue to reflect the transfer of goods or services to customers at an amount the entity expects to be paid in exchange for those goods and services and provide enhanced disclosures, all to provide more comprehensive guidance for transactions such as service revenue and contract modifications. The Company adopted the new revenue standard using the modified retrospective approach, and elected to apply the practical expedient to only assess the recognition of revenue for open contracts during the transition period. The effect of adoption did not have a material impact on the Company’s consolidated financial statements and there was no adjustment to the opening balance of retained earnings at January 1, 2018. The comparative information has not been restated and continues to be reported under the accounting standards in effect for that period. Under the new standard there was a change in the way the Company determines the unit of account for its third-party development projects. Under the previous guidance, the Company segmented revenue recognition between the development and construction phases of its contracts, recognizing each using the proportional performance method and the percentage of completion method, respectively. Under the new guidance, the entire development and construction contract represents a single performance obligation comprised of a series of distinct services to be satisfied over time, and a single transaction price to be recognized over the life of the contract using a time-based measure of progress. Any variable consideration included in the transaction price is estimated using the expected value approach and is only included to the extent that a significant revenue reversal is not likely to occur. The adoption of ASU 2014-09 resulted in differences in the timing and pattern of revenue recognition for such third-party development and construction management contracts; however, the change did not have a material impact on the Company’s consolidated financial statements. Third-party management services revenues consist of base fees earned as a result of managing all aspects of the property’s day-to-day operations, and incentive fees based on the managed property’s operating measures. There was no change in the Company’s recognition of base management fees. Incentive management fees were previously recognized when the incentive criteria had been met. Under the new guidance, incentive fees are estimated using the expected value approach and are included in the transaction price only to the extent that a significant revenue reversal is not likely to occur; however, the change did not have a material impact on the Company’s consolidated financial statements. There was no change to the Company’s revenue recognition methods for ancillary services and other non-lease related revenues as a result of the adoption of ASU 2014-09. Rental income from leasing arrangements is specifically excluded from ASU 2014-09, and is being evaluated as part of the adoption of the lease accounting standard, ASU 2016-02, discussed above. Accounting Standards Update 2017-05 (“ASU 2017-05”), “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets” On January 1, 2018, in conjunction with the adoption of ASU 2014-09, discussed above, the Company adopted ASU 2017-05. The purpose of this ASU is to eliminate the diversity in practice in accounting for derecognition of a nonfinancial asset and in-substance nonfinancial assets (only when the asset or asset group does not meet the definition of a business or the transaction is not a sale to a customer). The adoption of ASU 2017-05 did not have a material impact on the consolidated financial statements given the simplicity of the Company’s historical disposition transactions. Other In addition, on January 1, 2018, the Company adopted the following accounting pronouncements which did not have a material effect on the Company’s consolidated financial statements: • ASU 2017-09, “Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting” • ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.”
Interim Financial Statements	Interim Financial Statements The accompanying interim financial statements are unaudited, but have been prepared in accordance with GAAP for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair presentation of the financial statements of the Company for these interim periods have been included. Because of the seasonal nature of the Company’s operations, the results of operations and cash flows for any interim period are not necessarily indicative of results for other interim periods or for the full year. These financial statements should be read in conjunction with the financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 .
Investments in Real Estate	Investments in Real Estate Investments in real estate are recorded at historical cost. Major improvements that extend the life of an asset are capitalized and depreciated over the remaining useful life of the asset. The cost of ordinary repairs and maintenance are charged to expense when incurred. Depreciation and amortization are recorded on a straight-line basis over the estimated useful lives of the assets as follows: Buildings and improvements 7-40 years Leasehold interest - on-campus participating properties 25-34 years (shorter of useful life or respective lease term) Furniture, fixtures and equipment 3-7 years Project costs directly associated with the development and construction of an owned real estate project, which include interest, property taxes, and amortization of deferred financing costs, are capitalized as construction in progress. Upon completion of the project, costs are transferred into the applicable asset category and depreciation commences. Interest totaling approximately $2.6 million and $3.4 million was capitalized during the three months ended September 30, 2018 and 2017 , respectively, and interest totaling approximately $9.6 million and $13.5 million was capitalized during the nine months ended September 30, 2018 and 2017 , respectively. Management assesses whether there has been an impairment in the value of the Company’s investments in real estate whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Impairment is recognized when estimated expected future undiscounted cash flows are less than the carrying value of the property, or when a property meets the criteria to be classified as held for sale, at which time an impairment charge is recognized for any excess of the carrying value of the property over the expected net proceeds from the disposal. The estimation of expected future net cash flows is inherently uncertain and relies on assumptions regarding current and future economics and market conditions. If such conditions change, then an adjustment to the carrying value of the Company’s long-lived assets could occur in the future period in which the conditions change. To the extent that a property is impaired, the excess of the carrying amount of the property over its estimated fair value is charged to earnings. The Company believes that there were no impairments of the carrying values of its investments in real estate as of September 30, 2018 . The Company evaluates each acquisition to determine if the integrated set of assets and activities acquired meet the definition of a business. If either of the following criteria is met, the integrated set of assets and activities acquired would not qualify as a business: • Substantially all of the fair value of the gross assets acquired is concentrated in either a single identifiable asset or a group of similar identifiable assets; or • The integrated set of assets and activities is lacking, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs (i.e. revenue generated before and after the transaction). Property acquisitions deemed to qualify as a business are accounted for as business combinations, and the related acquisition costs are expensed as incurred. The Company allocates the purchase price of properties acquired in business combinations to net tangible and identified intangible assets based on their fair values. Fair value estimates are based on information obtained from a number of sources, including independent appraisals that may be obtained in connection with the acquisition or financing of the respective property, the Company’s own analysis of recently acquired and existing comparable properties in the Company’s portfolio, and other market data. Information obtained about each property, as a result of due diligence, marketing, and leasing activities, is also considered. The value allocated to land is generally based on the actual purchase price if acquired separately, or market research/comparables if acquired as part of an existing operating property. The value allocated to building is based on the fair value determined on an “as-if vacant” basis, which is estimated using a replacement cost approach that relies upon assumptions that the Company believes are consistent with current market conditions for similar properties. The value allocated to furniture, fixtures, and equipment is based on an estimate of the fair value of the appliances and fixtures inside the units. The Company has determined these estimates are primarily based upon unobservable inputs and therefore are considered to be Level 3 inputs within the fair value hierarchy. Acquisitions of properties that do not meet the definition of a business are accounted for as asset acquisitions. The accounting model for asset acquisitions is similar to the accounting model for business combinations except that the acquisition consideration (including transaction costs) is allocated to the individual assets acquired and liabilities assumed on a relative fair value basis. The relative fair values used to allocate the cost of an asset acquisition are determined using the same methodologies and assumptions as those utilized to determine fair value in a business combination.
Long-Lived Assets - Held for Sale	Long-Lived Assets–Held for Sale Long-lived assets to be disposed of are classified as held for sale in the period in which all of the following criteria are met: a. Management, having the authority to approve the action, commits to a plan to sell the asset. b. The asset is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets. c. An active program to locate a buyer and other actions required to complete the plan to sell the asset have been initiated. d. The sale of the asset is probable, and transfer of the asset is expected to qualify for recognition as a completed sale, within one year. e. The asset is being actively marketed for sale at a price that is reasonable in relation to its current fair value. f. Actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Concurrent with this classification, the asset is recorded at the lower of cost or fair value less estimated selling costs, and depreciation ceases. The Company did not have any properties classified as held for sale as of September 30, 2018 .
Restricted Cash	Restricted Cash Restricted cash consists of funds held in trust and invested in low risk investments, generally consisting of government backed securities, as permitted by the indentures of trusts, which were established in connection with three bond issues for the Company’s on-campus participating properties. Additionally, restricted cash includes escrow accounts held by lenders and resident security deposits, as required by law in certain states. Restricted cash also consists of escrow deposits made in connection with potential property acquisitions and development opportunities. These escrow deposits are invested in interest-bearing accounts at federally-insured banks. Realized and unrealized gains and losses are not material for the periods presented.
Consolidated VIEs	Consolidated VIEs The Company has investments in various entities that qualify as VIEs for accounting purposes and for which the Company is the primary beneficiary and therefore includes the entities in its consolidated financial statements. These VIEs include the Operating Partnership, six joint ventures that own a total of 15 operating properties, two properties subject to presale arrangements, and five properties owned under the on-campus participating property structure.
Third-Party Development Services Costs	Third-Party Development Services Costs Pre-development expenditures such as architectural fees, permits, and deposits associated with the pursuit of third-party and owned development projects are expensed as incurred, until such time that management believes it is probable that the contract will be executed and/or construction will commence, at which time the Company capitalizes the costs. Because the Company frequently incurs these pre-development expenditures before a financing commitment and/or required permits and authorizations have been obtained, the Company bears the risk of loss of these pre-development expenditures if financing cannot ultimately be arranged on acceptable terms or the Company is unable to successfully obtain the required permits and authorizations. As such, management evaluates the status of third-party and owned projects that have not yet commenced construction on a periodic basis and expenses any deferred costs related to projects whose current status indicates the commencement of construction is unlikely and/or the costs may not provide future value to the Company in the form of revenues. Such write-offs are included in third-party development and management services expenses (in the case of third-party development projects) or general and administrative expenses (in the case of owned development projects) on the accompanying consolidated statements of comprehensive income. As of September 30, 2018 , the Company has deferred approximately $13.7 million in pre-development costs related to third-party and owned development projects that have not yet commenced construction. Such costs are included in other assets on the accompanying consolidated balance sheets.
Earnings per Share - Company/Earnings per Unit - Operating Partnership	Earnings per Unit – Operating Partnership Basic earnings per OP Unit is computed using net income attributable to common unitholders and the weighted average number of common units outstanding during the period. Diluted earnings per OP Unit reflects the potential dilution that could occur if securities or other contracts to issue OP Units were exercised or converted into OP Units or resulted in the issuance of OP Units and then shared in the earnings of the Operating Partnership. Earnings per Share – Company Basic earnings per share is computed using net income attributable to common stockholders and the weighted average number of shares of the Company’s common stock outstanding during the period. Diluted earnings per share reflects common shares issuable from the assumed conversion of American Campus Communities Operating Partnership Units (“OP Units”) and common share awards granted. Only those items having a dilutive impact on basic earnings per share are included in diluted earnings per share.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Schedule of accounting pronouncements	In addition, the Company does not expect the following accounting pronouncements to have a material effect on its consolidated financial statements: Accounting Standards Update Effective Date ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract” January 1, 2020 ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” January 1, 2020 ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” January 1, 2019 ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” January 1, 2019 ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” January 1, 2020
Schedule of estimated useful lives of assets	Depreciation and amortization are recorded on a straight-line basis over the estimated useful lives of the assets as follows: Buildings and improvements 7-40 years Leasehold interest - on-campus participating properties 25-34 years (shorter of useful life or respective lease term) Furniture, fixtures and equipment 3-7 years
Schedule of potentially dilutive securities not included in calculating diluted earnings per share	The following potentially dilutive securities were outstanding for the three and nine months ended September 30, 2018 and 2017 , but were not included in the computation of diluted earnings per share because the effects of their inclusion would be anti-dilutive. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Common OP Units (Note 9) 602,264 1,011,674 831,328 1,023,248 Preferred OP Units (Note 9) 77,513 77,513 77,513 77,513 Unvested restricted stock awards (Note10) 883,595 818,547 — — Total potentially dilutive securities 1,563,372 1,907,734 908,841 1,100,761
Schedule of summary of elements used in calculating basic earnings per share/unit	The following is a summary of the elements used in calculating basic and diluted earnings per share: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator – basic and diluted earnings per share: Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 Net loss (income) attributable to noncontrolling interests 392 (79 ) 88 (587 ) Net (loss) income attributable to common stockholders (2,345 ) (1,312 ) 69,591 29,976 Amount allocated to participating securities (408 ) (360 ) (1,291 ) (1,217 ) Net (loss) income attributable to common stockholders $ (2,753 ) $ (1,672 ) $ 68,300 $ 28,759 Denominator: Basic weighted average common shares outstanding 137,022,012 136,421,198 136,742,094 134,708,361 Unvested restricted stock awards (Note 10) — — 918,708 877,489 Diluted weighted average common shares outstanding 137,022,012 136,421,198 137,660,802 135,585,850 Earnings per share: Net (loss) income attributable to common stockholders - basic and diluted $ (0.02 ) $ (0.01 ) $ 0.50 $ 0.21
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Schedule of summary of elements used in calculating basic earnings per share/unit	The following is a summary of the elements used in calculating basic and diluted earnings per unit: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator – basic and diluted earnings per unit: Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 Net loss (income) attributable to noncontrolling interests – partially owned properties 413 (57 ) 665 (259 ) Series A preferred unit distributions (31 ) (31 ) (93 ) (93 ) Amount allocated to participating securities (408 ) (360 ) (1,291 ) (1,217 ) Net (loss) income attributable to common unitholders $ (2,763 ) $ (1,681 ) $ 68,784 $ 28,994 Denominator: Basic weighted average common units outstanding 137,624,276 137,432,872 137,573,422 135,731,609 Unvested restricted stock awards (Note 10) — — 918,708 877,489 Diluted weighted average common units outstanding 137,624,276 137,432,872 138,492,130 136,609,098 Earnings per unit: Net (loss) income attributable to common unitholders - basic and diluted $ (0.02 ) $ (0.01 ) $ 0.50 $ 0.21

Acquisitions and Joint Ventur_2

Acquisitions and Joint Venture Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of asset acquisitions, by acquisition	During the nine months ended September 30, 2018 , the Company entered into two presale agreements to purchase two properties under development. The Company is obligated to purchase the properties for approximately $107.3 million , which includes the contractual purchase price and the cost of elected upgrades, as long as the developer meets certain construction completion deadlines and other closing conditions. Property Location Primary University Served Project Type Beds Scheduled Completion The Flex at Stadium Centre Tallahassee, FL Florida State University Off-campus 340 August 2019 959 Franklin (1) Eugene, OR University of Oregon Off-campus 443 September 2019 783 (1) As part of the presale agreement, the Company provided $15.6 million of mezzanine financing to the project.

Property Dispositions (Tables)

Property Dispositions (Tables)	9 Months Ended
	Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Schedule of properties classified as held for sale	In May 2018, the Company sold the following portfolio of three owned properties for approximately $245.0 million , resulting in net proceeds of approximately $242.3 million . The combined net gain on the portfolio disposition totaled approximately $42.3 million . Property Location Primary University Served Beds Icon Plaza Los Angeles, CA University of Southern California 253 West 27th Place Los Angeles, CA University of Southern California 475 The Standard Athens, GA University of Georgia 610 1,338

Investments in Owned Properti_2

Investments in Owned Properties (Tables)	9 Months Ended
	Sep. 30, 2018
Owned properties
Real Estate Properties [Line Items]
Schedule of real estate properties	Owned properties, both wholly-owned and those owned through investments in VIEs, consisted of the following: September 30, 2018 December 31, 2017 Land (1) $ 653,431 $ 646,991 Buildings and improvements 6,478,611 6,096,527 Furniture, fixtures and equipment 380,593 348,828 Construction in progress 191,879 393,045 7,704,514 7,485,391 Less accumulated depreciation (1,182,809 ) (1,035,027 ) Owned properties, net $ 6,521,705 $ 6,450,364 (1) The land balance above includes undeveloped land parcels with book values of approximately $ 54.4 million and $38.0 million as of September 30, 2018 and as of December 31, 2017 , respectively. It also includes land totaling approximately $10.3 million and $29.9 million as of September 30, 2018 and December 31, 2017 , respectively, related to properties under development.

On-Campus Participating Prope_2

On-Campus Participating Properties (Tables)	9 Months Ended
	Sep. 30, 2018
On-campus participating properties
Real Estate Properties [Line Items]
Schedule of real estate properties	On-campus participating properties are as follows: Historical Cost Lessor/University Lease Commencement Required Debt September 30, 2018 December 31, 2017 Texas A&M University System / Prairie View A&M University (1) 2/1/1996 9/1/2023 $ 45,446 $ 44,364 Texas A&M University System / Texas A&M International 2/1/1996 9/1/2023 7,077 6,923 Texas A&M University System / Prairie View A&M University (2) 10/1/1999 8/31/2025 28,758 27,802 8/31/2028 University of Houston System / University of Houston (3) 9/27/2000 8/31/2035 36,344 36,062 West Virginia University System / West Virginia University 7/16/2013 7/16/2045 45,289 44,845 162,914 159,996 Accumulated amortization (84,048 ) (78,192 ) On-campus participating properties, net $ 78,866 $ 81,804 (1) Consists of three phases placed in service between 1996 and 1998. (2) Consists of two phases placed in service in 2000 and 2003. (3) Consists of two phases placed in service in 2001 and 2005.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of summary of outstanding consolidated indebtedness, including unamortized debt premiums and discounts	A summary of the Company’s outstanding consolidated indebtedness, including unamortized debt premiums and discounts, is as follows: September 30, 2018 December 31, 2017 Debt secured by owned properties: Mortgage loans payable: Unpaid principal balance $ 765,922 $ 496,557 Unamortized deferred financing costs (2,017 ) (2,144 ) Unamortized debt premiums 12,813 19,006 776,718 513,419 Construction loans payable (1) 49,511 51,780 Unamortized deferred financing costs (697 ) (888 ) 825,532 564,311 Debt secured by on-campus participating properties: Mortgage loans payable (2) 68,337 69,776 Bonds payable 27,030 30,575 Unamortized deferred financing costs (554 ) (642 ) 94,813 99,709 Total secured mortgage, construction and bond debt 920,345 664,020 Unsecured notes, net of unamortized OID and deferred financing costs (3) 1,587,796 1,585,855 Unsecured term loans, net of unamortized deferred financing costs (4) 198,681 647,044 Unsecured revolving credit facility 266,900 127,600 Total debt, net $ 2,973,722 $ 3,024,519 (1) Construction loans payable relates to construction loans partially financing the development of two presale development projects. These properties are owned by entities determined to be VIEs for which the Company is the primary beneficiary. The creditors of these construction loans do not have recourse to the assets of the Company. (2) The creditors of mortgage loans payable related to on-campus participating properties do not have recourse to the assets of the Company. (3) Includes net unamortized original issue discount (“OID”) of $1.7 million and $1.9 million at September 30, 2018 and December 31, 2017 , respectively, and net unamortized deferred financing costs of $10.5 million and $12.2 million at September 30, 2018 and December 31, 2017 , respectively. (4) Includes net unamortized deferred financing costs of $1.3 million and $3.0 million at September 30, 2018 and December 31, 2017 , respectively. The Company has issued the following senior unsecured notes: Date Issued Amount % of Par Value Coupon Yield Original Issue Discount Term (Years) April 2013 $ 400,000 99.659 3.750 % 3.791 % $ 1,364 10 June 2014 400,000 99.861 4.125 % 4.269 % (1) 556 10 September 2015 400,000 99.811 3.350 % 3.391 % 756 5 October 2017 400,000 99.912 3.625 % 3.635 % 352 10 $ 1,600,000 $ 3,028 (1) The yield includes the effect of the amortization of interest rate swap terminations (see Note 11 ).

Stockholders' Equity _ Partne_2

Stockholders' Equity / Partners' Capital (Tables)	9 Months Ended
	Sep. 30, 2018
Stockholders' Equity Note [Abstract]
Summary of equity program activity	The following table presents activity under the Company’s previous ATM equity program during the three and nine months ended September 30, 2017 : Three Months Ended Nine Months Ended Total net proceeds $ 1,135 $ 188,538 Commissions paid to sales agents $ 14 $ 2,374 Weighted average price per share $ 48.09 $ 48.34 Shares of common stock sold 23,900 3,949,356

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Schedule of summarized activity of redeemable limited partners	Below is a table summarizing the activity of redeemable noncontrolling interests (ACC) / redeemable limited partners (Operating Partnership) for the nine months ended September 30, 2018 , which includes both the redeemable joint venture partners and OP Units discussed above: Balance, December 31, 2017 $ 132,169 Net income 554 Distributions (1,213 ) Conversion of OP Units into shares of ACC common stock (13,333 ) Contributions from noncontrolling interests 620 Adjustments to reflect OP Units at fair value 65,857 Balance, September 30, 2018 $ 184,654

Incentive Award Plan (Tables)

Incentive Award Plan (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of restricted stock units and awards	A summary of RSUs as of September 30, 2018 and activity during the nine months then ended is presented below: Number of RSUs Outstanding at December 31, 2017 — Granted 27,376 Settled in common shares (27,376 ) Outstanding at September 30, 2018 — A summary of RSAs as of September 30, 2018 and activity during the nine months then ended is presented below: Number of RSAs Nonvested balance at December 31, 2017 810,870 Granted 357,387 Vested (1) (240,845 ) Forfeited (48,198 ) Nonvested balance at September 30, 2018 879,214 (1) Includes shares withheld to satisfy tax obligations upon vesting.

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of financial instruments measured at fair value	Disclosures concerning financial instruments measured at fair value are as follows: Fair Value Measurements as of September 30, 2018 December 31, 2017 Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mezzanine: Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership) $ — $ 27,672 $ 156,982 $ 184,654 $ — $ 44,503 $ 87,666 $ 132,169
Schedule of estimated fair value and related carrying amounts of mortgage loans and bonds payable	The table below contains the estimated fair value and related carrying amounts for the Company’s financial instruments as of September 30, 2018 and December 31, 2017 : September 30, 2018 December 31, 2017 Estimated Fair Value Carrying Amount Estimated Fair Value Carrying Amount Assets: Loans receivable $ 54,140 $ 60,424 $ 54,140 $ 57,948 Liabilities: Unsecured notes $ 1,554,144 $ 1,587,796 (1) $ 1,620,839 $ 1,585,855 (1) Mortgage loans payable (4) $ 768,542 $ 803,389 (2) $ 571,676 $ 582,927 (2) Bonds payable $ 28,544 $ 26,720 (3) $ 32,552 $ 30,201 (3) (1) Includes net unamortized OID and net unamortized deferred financing costs (see Note 7 ). (2) Includes net unamortized debt premiums and discounts and net unamortized deferred financing costs (see Note 7 ). (3) Includes net unamortized deferred financing costs (see Note 7 ). (4) In July 2018, the fixed feature of a mortgage loan secured by an on-campus participating property expired, and the mortgage loan became classified as variable rate debt.

Segments (Tables)

Segments (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of segment information	Three Months Ended Nine Months Ended 2018 2017 2018 2017 Owned Properties Rental revenues and other income $ 203,526 $ 184,282 $ 600,138 $ 533,866 Interest income 382 385 1,146 1,161 Total revenues from external customers 203,908 184,667 601,284 535,027 Operating expenses before depreciation, amortization, and ground/facility lease expense (107,997 ) (99,423 ) (282,193 ) (249,552 ) Ground/facility lease expense (2,306 ) (1,877 ) (6,293 ) (5,163 ) Interest expense, net (1) (5,622 ) (1,540 ) (9,011 ) (1,194 ) Operating income before depreciation and amortization $ 87,983 $ 81,827 $ 303,787 $ 279,118 Depreciation and amortization $ 62,909 $ 58,339 $ 185,171 $ 161,341 Capital expenditures $ 144,910 $ 196,910 $ 428,065 $ 473,638 On-Campus Participating Properties Rental revenues and other income $ 6,980 $ 6,799 $ 23,605 $ 23,128 Interest income 43 24 105 47 Total revenues from external customers 7,023 6,823 23,710 23,175 Operating expenses before depreciation, amortization, and ground/facility lease expense (3,875 ) (3,923 ) (11,030 ) (11,080 ) Ground/facility lease expense (645 ) (452 ) (2,233 ) (1,988 ) Interest expense (1,282 ) (1,312 ) (3,804 ) (3,987 ) Operating income before depreciation and amortization $ 1,221 $ 1,136 $ 6,643 $ 6,120 Depreciation and amortization $ 1,962 $ 1,892 $ 5,856 $ 5,621 Capital expenditures $ 1,394 $ 2,039 $ 2,918 $ 2,909 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Development Services Development and construction management fees $ 835 $ 3,566 $ 3,883 $ 4,697 Operating expenses (2,056 ) (2,114 ) (5,976 ) (5,971 ) Operating (loss) income before depreciation and amortization $ (1,221 ) $ 1,452 $ (2,093 ) $ (1,274 ) Property Management Services Property management fees from external customers $ 2,128 $ 2,291 $ 7,311 $ 7,193 Operating expenses (1,775 ) (1,765 ) (5,597 ) (5,818 ) Operating income before depreciation and amortization $ 353 $ 526 $ 1,714 $ 1,375 Reconciliations Total segment revenues and other income $ 213,894 $ 197,347 $ 636,188 $ 570,092 Unallocated interest income earned on investments and corporate cash 849 850 2,489 2,515 Total consolidated revenues, including interest income $ 214,743 $ 198,197 $ 638,677 $ 572,607 Segment operating income before depreciation and amortization $ 88,336 $ 84,941 $ 310,051 $ 285,339 Depreciation and amortization (67,247 ) (62,271 ) (199,191 ) (172,588 ) Net unallocated expenses relating to corporate interest and overhead (24,615 ) (23,636 ) (83,958 ) (65,448 ) Gain (loss) from disposition of real estate — — 42,314 (632 ) Other operating and nonoperating income 570 — 3,218 — Loss from early extinguishment of debt — — (784 ) — Provision for real estate impairment — — — (15,317 ) Income tax provision 219 (267 ) (2,147 ) (791 ) Net (loss) income $ (2,737 ) $ (1,233 ) $ 69,503 $ 30,563 (1) Net of capitalized interest and amortization of debt premiums.

Organization and Description _2

Organization and Description of Business (Details)	9 Months Ended
	Sep. 30, 2018university_systemPropertyBed
Real Estate Properties [Line Items]
Number of properties	168
Number of beds | Bed	103,500
Minimum
Real Estate Properties [Line Items]
Initial term of contract	1 year
Maximum
Real Estate Properties [Line Items]
Initial term of contract	5 years
Owned properties | Off Campus Properties
Real Estate Properties [Line Items]
Number of properties	131
Owned properties | American Campus Equity
Real Estate Properties [Line Items]
Number of housing properties	32
Owned properties | On-campus participating properties
Real Estate Properties [Line Items]
Number of properties	5
Owned properties | Under Development
Real Estate Properties [Line Items]
Number of beds | Bed	3,200
Management And Leasing Services
Real Estate Properties [Line Items]
Number of properties	34
Number of beds | Bed	28,400
Investments in real estate, net
Real Estate Properties [Line Items]
Number of properties	202
Number of beds | Bed	131,900
Owned On Campus Properties | American Campus Equity
Real Estate Properties [Line Items]
Number of university systems | university_system	15
Owned On Campus Properties | Under Development
Real Estate Properties [Line Items]
Number of properties under development	5
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Real Estate Properties [Line Items]
Limited partner interest (percent)	99.50%
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Maximum
Real Estate Properties [Line Items]
Ownership interest (percent)	1.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)PropertyleaseEntityagreement	Sep. 30, 2017USD ($)Property	Sep. 30, 2018USD ($)PropertyleaseEntityagreement	Sep. 30, 2017USD ($)Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties subject to ground leases | lease	24		24
Number of properties subject to corporate office headquarters leases | Property	2		2
Net cash provided by operating activities			$ 266,933	$ 245,689
Net cash used in investing activities			216,111	769,045
Net cash provided by financing activities			(25,053)	518,564
Capitalized interest	$ 2,600	$ 3,400	$ 9,600	$ 13,500
Number of third-party joint venture partners (entities) | Entity	6		6
Number of properties | Property	168		168
Number of properties, under development | Property	3		3
Number of properties subject to presale arrangements | agreement	2		2
Deferred pre-development costs	$ 13,700		$ 13,700
In-process development properties
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties | Property		3		3
Number of properties, under development | Property	2		2
Number of properties subject to presale arrangements | agreement	2		2
On-campus participating properties
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties | Property	5		5
Six joint ventures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties | Property	15		15
Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net change in cash, cash equivalents, and restricted cash				$ 25,800
Net cash provided by operating activities				600
Net cash used in investing activities				1,300
Net cash provided by financing activities				$ (900)

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	9 Months Ended
	Sep. 30, 2018
Minimum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Minimum | Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Maximum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Maximum | Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
On-campus participating properties | Minimum | Leasehold interest
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
On-campus participating properties | Maximum | Leasehold interest
Property, Plant and Equipment [Line Items]
Estimated useful life	34 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Potentially Dilutive Securities Not Included in Calculating Diluted Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	1,563,372	1,907,734	908,841	1,100,761
Common OP Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	602,264	1,011,674	831,328	1,023,248
Preferred OP Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	77,513	77,513	77,513	77,513
Unvested restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	883,595	818,547	0	0

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Elements Used in Calculating Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator – basic and diluted earnings per share:
Net (loss) income	$ (2,737)	$ (1,233)	$ 69,503	$ 30,563
Net loss (income) attributable to noncontrolling interests	392	(79)	88	(587)
Net (loss) income attributable to common stockholders	(2,345)	(1,312)	69,591	29,976
Amount allocated to participating securities	(408)	(360)	(1,291)	(1,217)
Net (loss) income attributable to common unitholders	$ (2,753)	$ (1,672)	$ 68,300	$ 28,759
Denominator:
Basic weighted average common shares outstanding (in shares)	137,022,012	136,421,198	136,742,094	134,708,361
Diluted weighted average common shares outstanding (in shares)	137,022,012	136,421,198	137,660,802	135,585,850
Earnings per share:
Net (loss) income attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.02)	$ (0.01)	$ 0.50	$ 0.21
Unvested restricted stock awards
Denominator:
Unvested restricted stock awards (in shares)	0	0	918,708	877,489

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Summary of Elements Used in Calculating Basic and Diluted Earnings per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator – basic and diluted earnings per unit:
Net (loss) income	$ (2,737)	$ (1,233)	$ 69,503	$ 30,563
Net income attributable to noncontrolling interests	392	(79)	88	(587)
Net (loss) income attributable to common unitholders	(2,753)	(1,672)	68,300	28,759
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Numerator – basic and diluted earnings per unit:
Net (loss) income	(2,737)	(1,233)	69,503	30,563
Series A preferred unit distributions	(31)	(31)	(93)	(93)
Amount allocated to participating securities	(408)	(360)	(1,291)	(1,217)
Net (loss) income attributable to common unitholders	$ (2,763)	$ (1,681)	$ 68,784	$ 28,994
Denominator:
Basic weighted average common units outstanding (in units)	137,624,276	137,432,872	137,573,422	135,731,609
Diluted weighted average common units outstanding (in units)	137,624,276	137,432,872	138,492,130	136,609,098
Earnings per unit:
Net (loss) income attributable to common unitholders - basic and diluted (in dollars per unit)	$ (0.02)	$ (0.01)	$ 0.50	$ 0.21
Partially owned properties | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Numerator – basic and diluted earnings per unit:
Net income attributable to noncontrolling interests	$ 413	$ (57)	$ 665	$ (259)
Unvested restricted stock awards | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Denominator:
Unvested restricted stock awards (in units)	0	0	918,708	877,489

Acquisitions and Joint Ventur_3

Acquisitions and Joint Venture Investments - Narrative (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended		15 Months Ended
	Sep. 30, 2018USD ($)PropertyBedpresale_agreementagreement	Aug. 31, 2018USD ($)Bed	Sep. 30, 2019USD ($)Bed	Sep. 30, 2017USD ($)PropertyBedland_parcel	Sep. 30, 2018USD ($)PropertyBedpresale_agreementagreement	Sep. 30, 2017USD ($)PropertyBedland_parcel	Dec. 31, 2019USD ($)
Business Acquisition [Line Items]
Number of presale agreements | agreement	2				2
Number of properties, under development | Property	3				3
Number of beds | Bed	103,500				103,500
Cash paid for land acquisitions		$ 16,500			$ 26,534	$ 8,886
Number of properties | Property	168				168
Asset acquisition, consideration transferred						302,300
Presale development properties
Business Acquisition [Line Items]
Number of presale agreements | presale_agreement	2				2
Number of properties, under development | Property	2				2
Estimated development costs					$ 107,300
Owned properties
Business Acquisition [Line Items]
Asset acquisition, consideration transferred						$ 158,500
In-process development properties
Business Acquisition [Line Items]
Number of presale agreements | agreement	2				2
Number of properties, under development | Property	2				2
Number of properties | Property				3		3
Land
Business Acquisition [Line Items]
Cash paid for land acquisitions						$ 8,900
Non-cash consideration						3,100
Asset acquisition, consideration transferred		$ 16,600				$ 12,000
Number of land parcels | land_parcel				5		5
Asset acquisitions, fair value				$ 12,000		$ 12,000
Land | In-process development properties
Business Acquisition [Line Items]
Asset acquisition, consideration transferred						$ 9,000
Core Transaction
Business Acquisition [Line Items]
Number of beds | Bed				3,776		3,776
Number of housing properties | Property				7		7
Limited partner interest (percent)				100.00%		100.00%
Number of properties | Property				2		2
Number of joint ventures | Property				2		2
Asset acquisition, consideration transferred	$ 83,700			$ 306,000		$ 146,100
Other Acquisitions
Business Acquisition [Line Items]
Number of beds | Bed				982		982
Number of properties | Property				2		2
The Edge - Stadium Centre | Pre-Sale Arrangement | Owned properties
Business Acquisition [Line Items]
Number of beds | Bed		412
Cash paid for land acquisitions		$ 10,000
Asset acquisition, consideration transferred		$ 42,600
Scenario, Forecast | Presale development properties
Business Acquisition [Line Items]
Estimated development costs			$ 107,300
Scenario, Forecast | In-process development properties
Business Acquisition [Line Items]
Number of beds | Bed			783
Scenario, Forecast | Core Transaction
Business Acquisition [Line Items]
Asset acquisition, consideration transferred							$ 200,900

Acquisitions and Joint Ventur_4

Acquisitions and Joint Venture Investments - Summary of Acquisitions (Details) $ in Millions	Sep. 30, 2019USD ($)Bed	Aug. 31, 2019Bed	Sep. 30, 2018Bed
Business Acquisition [Line Items]
Number of beds			103,500
Scenario, Forecast | In-process development properties
Business Acquisition [Line Items]
Number of beds	783
Mezzanine financing provided to private developer | $	$ 15.6
Scenario, Forecast | The Flex at Stadium Centre | In-process development properties
Business Acquisition [Line Items]
Number of beds		340
Scenario, Forecast | 959 Franklin | In-process development properties
Business Acquisition [Line Items]
Number of beds	443

Property Dispositions - Narrati

Property Dispositions - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2018USD ($)PropertyBed	Sep. 30, 2018USD ($)Bed	Sep. 30, 2017USD ($)Bed	Sep. 30, 2018USD ($)Bed	Sep. 30, 2017USD ($)Bed
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from disposition of properties				$ 242,284	$ 24,462
Gain (loss) from disposition of real estate		$ 0	$ 0	$ 42,314	(632)
Number of beds | Bed		103,500		103,500
Provision for real estate impairment		$ 0	0	$ 0	15,317
Proceeds from secured debt issuance	$ 330,000			$ 330,000	0
Allianz Real Estate
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash contribution	$ 373,100
ACC/Allianz Joint Venture | Allianz Real Estate
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Minority interest (percent)	45.00%
Disposal Group, Not Discontinued Operations | Owned properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price of disposed property	$ 245,000
Proceeds from disposition of properties	242,300
Gain (loss) from disposition of real estate	$ 42,300
Disposal Group, Not Discontinued Operations | Owned properties | ACC/Allianz Joint Venture Transaction
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | Property	7
Number of beds | Bed	4,611
Disposal Group, Not Discontinued Operations | The Province - Dayton | Owned properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price of disposed property			$ 25,000		25,000
Proceeds from disposition of properties					24,500
Gain (loss) from disposition of real estate					$ (600)
Number of beds | Bed			657		657
Provision for real estate impairment					$ 4,900

Property Dispositions - Summary

Property Dispositions - Summary of Properties Classified as Held for Sale (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - Wholly Owned Properties Sold	1 Months Ended
	May 31, 2018Bed
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of beds in properties sold	1,338
Icon Plaza
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of beds in properties sold	253
West 27th Place
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of beds in properties sold	475
The Standard
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of beds in properties sold	610

Investments in Owned Properti_3

Investments in Owned Properties (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Real Estate Properties [Line Items]
Owned properties, net	$ 6,600,571	$ 6,532,168
Undeveloped land parcels	54,400	38,000
Owned properties
Real Estate Properties [Line Items]
Land	653,431	646,991
Buildings and improvements	6,478,611	6,096,527
Furniture, fixtures and equipment	380,593	348,828
Construction in progress	191,879	393,045
Real estate properties gross	7,704,514	7,485,391
Less accumulated depreciation	(1,182,809)	(1,035,027)
Owned properties, net	6,521,705	6,450,364
Under Development
Real Estate Properties [Line Items]
Undeveloped land parcels	$ 10,300	$ 29,900

On-Campus Participating Prope_3

On-Campus Participating Properties (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)phase	Dec. 31, 2017USD ($)
Real Estate Properties [Line Items]
Owned properties, net	$ 6,600,571	$ 6,532,168
On-campus participating properties
Real Estate Properties [Line Items]
Historical Cost	162,914	159,996
Accumulated amortization	(84,048)	(78,192)
Owned properties, net	$ 78,866	81,804
On-campus participating properties | Texas A and M International
Real Estate Properties [Line Items]
Lease Commencement	Feb. 1, 1996
Required Debt Repayment	Sep. 1, 2023
Historical Cost	$ 7,077	6,923
Texas A&M University System / Prairie View A&M University between 1996 and 1998 | Prairie View A and M University
Real Estate Properties [Line Items]
Number of project phases | phase	3
Texas A&M University System / Prairie View A&M University between 1996 and 1998 | On-campus participating properties | Prairie View A and M University
Real Estate Properties [Line Items]
Lease Commencement	Feb. 1, 1996
Required Debt Repayment	Sep. 1, 2023
Historical Cost	$ 45,446	44,364
Texas A&M University System / Prairie View A&M University between 2000 and 2003 | Prairie View A and M University
Real Estate Properties [Line Items]
Number of project phases | phase	2
Texas A&M University System / Prairie View A&M University between 2000 and 2003 | On-campus participating properties | Prairie View A and M University
Real Estate Properties [Line Items]
Lease Commencement	Oct. 1, 1999
Historical Cost	$ 28,758	27,802
University of Houston System / University of Houston | University Of Houston
Real Estate Properties [Line Items]
Number of project phases | phase	2
University of Houston System / University of Houston | On-campus participating properties | University Of Houston
Real Estate Properties [Line Items]
Lease Commencement	Sep. 27, 2000
Required Debt Repayment	Aug. 31, 2035
Historical Cost	$ 36,344	36,062
West Virginia University System / West Virginia University | On-campus participating properties | West Virginia University
Real Estate Properties [Line Items]
Lease Commencement	Jul. 16, 2013
Required Debt Repayment	Jul. 16, 2045
Historical Cost	$ 45,289	$ 44,845
Minimum | Texas A&M University System / Prairie View A&M University between 2000 and 2003 | On-campus participating properties | Prairie View A and M University
Real Estate Properties [Line Items]
Required Debt Repayment	Aug. 31, 2025
Maximum | Texas A&M University System / Prairie View A&M University between 2000 and 2003 | On-campus participating properties | Prairie View A and M University
Real Estate Properties [Line Items]
Required Debt Repayment	Aug. 31, 2028

Debt - Summary of Outstanding C

Debt - Summary of Outstanding Consolidated Indebtedness, Including Unamortized Debt Premiums and Discounts (Details) $ in Thousands	1 Months Ended	9 Months Ended
	May 31, 2018Property	Sep. 30, 2018USD ($)Property	Dec. 31, 2017USD ($)	Sep. 30, 2017Property	Aug. 31, 2017USD ($)
Debt Instrument [Line Items]
Secured mortgage, construction and bond debt, net		$ 920,345	$ 664,020
Total debt, net		$ 2,973,722	3,024,519
Number of properties | Property		168
Mortgage loans payable
Debt Instrument [Line Items]
Secured mortgage, construction and bond debt, net					$ 27,400
Unsecured debt
Debt Instrument [Line Items]
Unamortized deferred financing costs		$ (10,500)	(12,200)
Unamortized original issue discount		1,700	1,900
Term loans
Debt Instrument [Line Items]
Unamortized deferred financing costs		(1,300)	(3,000)
Wholly-owned properties, net
Debt Instrument [Line Items]
Total debt, net		825,532	564,311
Number of properties sold | Property	7
Wholly-owned properties, net | Mortgage loans payable
Debt Instrument [Line Items]
Principal outstanding		765,922	496,557
Secured mortgage, construction and bond debt, net		776,718	513,419
Unamortized deferred financing costs		(2,017)	(2,144)
Unamortized debt premiums		$ 12,813	19,006
Number of properties sold | Property		1
Wholly-owned properties, net | Construction loans payable
Debt Instrument [Line Items]
Principal outstanding		$ 49,511	51,780
Unamortized deferred financing costs		(697)	(888)
On-campus participating properties, net
Debt Instrument [Line Items]
Unamortized deferred financing costs		(554)	(642)
Total debt, net		$ 94,813	99,709
Number of properties | Property		5
On-campus participating properties, net | Mortgage loans payable
Debt Instrument [Line Items]
Principal outstanding		$ 68,337	69,776
On-campus participating properties, net | Bonds payable
Debt Instrument [Line Items]
Principal outstanding		$ 27,030	30,575
In-process development properties
Debt Instrument [Line Items]
Number of properties | Property				3
In-process development properties | Construction loans payable
Debt Instrument [Line Items]
Number of properties sold | Property		2
Unsecured notes, net
Debt Instrument [Line Items]
Unsecured debt		$ 1,587,796	1,585,855
Unsecured term loans, net
Debt Instrument [Line Items]
Unsecured debt		198,681	647,044
Unsecured revolving credit facility
Debt Instrument [Line Items]
Unsecured debt		$ 266,900	$ 127,600

Debt - Narrative (Details)

Debt - Narrative (Details)	1 Months Ended			3 Months Ended		9 Months Ended
	Aug. 31, 2018USD ($)	May 31, 2018USD ($)Property	Jun. 30, 2017USD ($)	Sep. 30, 2018USD ($)Property	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Property	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)	Aug. 31, 2017USD ($)
Debt Instrument [Line Items]
Repayments of notes payable						$ 9,728,000	$ 10,582,000
Defeasance costs related to early extinguishment of debt						(2,726,000)	0
Loss from early extinguishment of debt				$ 0	$ 0	784,000	0
Pay-off of mortgage and construction loans						146,165,000	99,185,000
Mortgage loans payable				920,345,000		920,345,000		$ 664,020,000
Other operating income				$ 0	$ 0	0	15,317,000
Repayments of unsecured debt						$ 450,000,000	0
Unsecured revolving credit facility | Credit Agreement
Debt Instrument [Line Items]
Stated percentage				2.19%		2.19%
Line of credit, required unused commitment fee per annum (percent)						0.20%
Weighted average annual interest rate (percent)				3.39%		3.39%
Basis spread on variable rate						1.00%
Owned properties
Debt Instrument [Line Items]
Number of properties sold | Property		7
Owned properties | Disposal Group, Not Discontinued Operations
Debt Instrument [Line Items]
Number of properties sold | Property		3
Core Joint Venture II | In-process development properties
Debt Instrument [Line Items]
Pay-off of mortgage and construction loans	$ 19,300,000			$ 71,000,000
Mortgages
Debt Instrument [Line Items]
Mortgage loans payable									$ 27,400,000
Other operating income			$ 15,300,000
Mortgages | ACC/Alianz Joint Venture Secured Debt
Debt Instrument [Line Items]
Fixed rate secured mortgage debt		$ 330,000,000
Stated percentage		4.07%
Mortgages | Owned properties
Debt Instrument [Line Items]
Repayments of notes payable						$ 55,900,000	$ 30,500,000
Number of fixed rate mortgage debt secured owned properties.				3	0	3	0
Defeasance costs related to early extinguishment of debt						$ (2,700,000)
Number of properties sold | Property						1
Write off of deffered financing costs, premiums and discounts						$ 1,900,000
Loss from early extinguishment of debt						800,000
Mortgage loans payable				$ 776,718,000		$ 776,718,000		513,419,000
Unsecured debt | Unsecured revolving credit facility
Debt Instrument [Line Items]
Line of credit, required unused commitment fee per annum (percent)						0.20%
Current borrowing capacity of credit facility				$ 433,100,000		$ 433,100,000
Unsecured debt | Unsecured revolving credit facility | Fifth Amended And Restated Credit Agreement
Debt Instrument [Line Items]
Credit facility					$ 700,000,000		$ 700,000,000
Credit facility, additional borrowing capacity (up to)					500,000,000		500,000,000
Unsecured debt | Unsecured revolving credit facility | Credit Agreement
Debt Instrument [Line Items]
Credit facility					$ 700,000,000		$ 700,000,000
Unsecured debt | Unsecured revolving credit facility | Term Loan III Facility
Debt Instrument [Line Items]
Write off of deffered financing costs, premiums and discounts		$ 900,000
Repayments of unsecured debt		300,000,000
Unsecured debt | Unsecured revolving credit facility | Term Loan I Facility
Debt Instrument [Line Items]
Repayments of unsecured debt		$ 150,000,000
Unsecured debt | Unsecured revolving credit facility | Term Loan II Facility
Debt Instrument [Line Items]
Stated percentage				2.10%		2.10%
Credit facility								200,000,000
Weighted average annual interest rate (percent)				3.20%		3.20%
Basis spread on variable rate						1.10%
Line of credit facility, accordion feature (up to)								$ 100,000,000

Debt - Summary of Senior Unsecu

Debt - Summary of Senior Unsecured Notes (Details) - AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.	9 Months Ended
	Sep. 30, 2018USD ($)
Senior notes
Debt Instrument [Line Items]
Amount	$ 1,600,000,000
Original Issue Discount	3,028,000
Senior notes - April 2013
Debt Instrument [Line Items]
Amount	$ 400,000,000
% of Par Value	99.659%
Coupon (percent)	3.75%
Yield (percent)	3.791%
Original Issue Discount	$ 1,364,000
Term (Years)	10 years
Senior notes - June 2014
Debt Instrument [Line Items]
Amount	$ 400,000,000
% of Par Value	99.861%
Coupon (percent)	4.125%
Yield (percent)	4.269%
Original Issue Discount	$ 556,000
Term (Years)	10 years
Senior notes - September 2015
Debt Instrument [Line Items]
Amount	$ 400,000,000
% of Par Value	99.811%
Coupon (percent)	3.35%
Yield (percent)	3.391%
Original Issue Discount	$ 756,000
Term (Years)	5 years
Senior notes - October 2017
Debt Instrument [Line Items]
Amount	$ 400,000,000
% of Par Value	99.912%
Coupon (percent)	3.625%
Yield (percent)	3.635%
Original Issue Discount	$ 352,000
Term (Years)	10 years

Stockholders' Equity _ Partne_3

Stockholders' Equity / Partners' Capital - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	May 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Number of shares in deferred compensation plan (in shares)	69,603		63,778
Treasury Stock
Schedule of Equity Method Investments [Line Items]
Number of shares deposited into deferred compensation plan (in shares)	12,956
Number of shares withdrawn from deferred compensation plan (in shares)	7,131
Number of shares in deferred compensation plan (in shares)	69,603
ATM Equity Program
Schedule of Equity Method Investments [Line Items]
ATM equity program, aggregate offering price authorized (up to $500 million)	$ 500	$ 500
At The Market Program Expired May 2018, Included In ATM Equity Program
Schedule of Equity Method Investments [Line Items]
ATM equity program, aggregate offering price authorized (up to $500 million)		$ 233

Stockholders' Equity _ Partne_4

Stockholders' Equity / Partners' Capital - Summary of Equity Program Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Class of Stock [Line Items]
Total net proceeds		$ 0	$ 190,912
ATM Equity Program
Class of Stock [Line Items]
Total net proceeds	$ 1,135		188,538
Commissions paid to sales agents	$ 14		$ 2,374
Weighted average price per share (in dollars per share)	$ 48.09		$ 48.34
Shares of common stock sold (in shares)	23,900		3,949,356

Noncontrolling Interests - Narr

Noncontrolling Interests - Narrative (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)PropertyEntityagreementshares	Dec. 31, 2017shares	Sep. 30, 2017Property
Noncontrolling Interest [Line Items]
Number of third-party joint venture partners (entities) | Entity	6
Number of properties	168
Number of presale agreements | agreement	2
Number of properties, under development	3
Common OP Unit
Noncontrolling Interest [Line Items]
Conversion of operating partnership units to common stock (in shares) | shares	412,343	22,000
In-process development properties
Noncontrolling Interest [Line Items]
Number of properties			3
Number of presale agreements | agreement	2
Number of properties, under development	2
Three off-campus properties | In-process development properties
Noncontrolling Interest [Line Items]
Number of properties	10
Core Transaction
Noncontrolling Interest [Line Items]
Number of properties			2
Number of joint ventures			2
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Noncontrolling Interest [Line Items]
Equity interests held by owners of common units and preferred units (percent)	0.50%	0.80%
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Three off-campus properties
Noncontrolling Interest [Line Items]
Number of third-party joint venture partners (entities) | Entity	4
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Redeemable noncontrolling interests
Noncontrolling Interest [Line Items]
Noncontrolling interest, change in redemption value | $	$ 68.7

Noncontrolling Interests - Summ

Noncontrolling Interests - Summarized Activity of Redeemable Limited Partners (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	$ 132,169
Distributions	(151,271)
Conversion of OP Units into shares of ACC common stock	(13,332)
Contributions from noncontrolling interests	212,481
Ending balance	184,654
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P.
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	132,169
Distributions	(151,271)
Conversion of OP Units into shares of ACC common stock	(13,332)
Contributions from noncontrolling interests	212,481
Ending balance	184,654
AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Redeemable noncontrolling interests
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	132,169
Net income	554
Distributions	(1,213)
Conversion of OP Units into shares of ACC common stock	(13,333)
Contributions from noncontrolling interests	620
Adjustments to reflect OP Units at fair value	65,857
Ending balance	$ 184,654

Incentive Award Plan - Narrativ

Incentive Award Plan - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2018	May 31, 2018	Mar. 31, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense							$ 900
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense					$ 2,700	$ 2,400	$ 8,800	$ 10,600
Number of shares vested (in shares)							240,845
Newly Appointed Board Member | Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted	$ 150,000		$ 115
Allocated share-based compensation expense							$ 200
Board of Directors Chairman | Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted		$ 160
All Other Members | Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted		$ 115
Chief Financial Officer | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense								$ 2,400
Number of shares vested (in shares)				46,976
2018 Incentive Award Plan | Select Employees and Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)		3,500,000

Incentive Award Plan - Summary

Incentive Award Plan - Summary of Restricted Stock Units (Details) - Restricted stock units (RSUs)	9 Months Ended
	Sep. 30, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (shares)	0
Granted (shares)	27,376
Settled in common shares (shares)	(27,376)
Ending balance (shares)	0

Incentive Award Plan - Summar_2

Incentive Award Plan - Summary of Restricted Stock Awards (Details) - Restricted stock awards	9 Months Ended
	Sep. 30, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (shares)	810,870
Granted (shares)	357,387
Vested (shares)	(240,845)
Forfeited (shares)	(48,198)
Ending balance (shares)	879,214

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Details) $ in Millions	Sep. 30, 2018USD ($)
Interest rate swaps contracts
Derivative [Line Items]
Notional amount	$ 96.7

Fair Value Disclosures - Financ

Fair Value Disclosures - Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Mezzanine:
Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership)	$ 184,654	$ 132,169
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1)
Mezzanine:
Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership)	0	0
Significant Other Observable Inputs (Level 2)
Mezzanine:
Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership)	27,672	44,503
Significant Unobservable Inputs (Level 3)
Mezzanine:
Redeemable noncontrolling interests (Company)/Redeemable limited partners (Operating Partnership)	$ 156,982	$ 87,666

Fair Value Disclosures - Estima

Fair Value Disclosures - Estimated Fair Value and Related Carrying Amounts of Mortgage Loans and Bonds Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Estimated Fair Value
Assets:
Loans receivable	$ 54,140	$ 54,140
Liabilities:
Unsecured notes	1,554,144	1,620,839
Mortgage loans payable	768,542	571,676
Bonds payable	28,544	32,552
Carrying Amount
Assets:
Loans receivable	60,424	57,948
Liabilities:
Unsecured notes	1,587,796	1,585,855
Mortgage loans payable	803,389	582,927
Bonds payable	$ 26,720	$ 30,201

Commitments and Contingencies (

Commitments and Contingencies (Details)	1 Months Ended	3 Months Ended			9 Months Ended
	Aug. 31, 2013USD ($)extension	Sep. 30, 2019USD ($)agreement	Dec. 31, 2018USD ($)	Sep. 30, 2017USD ($)Entity	Sep. 30, 2018USD ($)PropertyEntity	Sep. 30, 2017USD ($)Entity
Loss Contingencies [Line Items]
Number of properties | Property					168
Number of properties, under development | Property					3
Number of third-party joint venture partners (entities) | Entity					6
Asset acquisition, consideration transferred						$ 302,300,000
Alternate Housing Guarantees
Loss Contingencies [Line Items]
Guarantee expiration period					5 days
Project Cost Guarantees
Loss Contingencies [Line Items]
Guarantee expiration period					1 year
Third-Party Development Projects
Loss Contingencies [Line Items]
Commitment under third-party development project					$ 10,300,000
Performance Guarantee
Loss Contingencies [Line Items]
Guarantor obligations, maximum exposure					$ 2,100,000
Under Development
Loss Contingencies [Line Items]
Number of properties | Property					2
Drexel University Property
Loss Contingencies [Line Items]
Lease term	40 years
Number of lease renewal options | extension	3
Lease extension period	10 years
Commitment to pay real estate transfer taxes, amount (not more than)	$ 1,800,000
Real estate transfer taxes paid upon conveyance of land	600,000
Maximum | Drexel University Property
Loss Contingencies [Line Items]
Commitment to pay real estate transfer taxes, amount (not more than)	$ 2,400,000
Construction contracts
Loss Contingencies [Line Items]
Other commitment					$ 132,900,000
Presale development properties
Loss Contingencies [Line Items]
Number of properties, under development | Property					2
Estimated development costs					$ 107,300,000
Estimated development costs, remaining obligation to be funded					$ 90,000,000
Core Transaction | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Consolidated properties
Loss Contingencies [Line Items]
Number of third-party joint venture partners (entities) | Entity				2		2
Period of option to purchase remaining interest in joint venture				2 years
Option to purchase remaining interest in joint venture				$ 200,900,000
Scenario, Forecast | Presale development properties
Loss Contingencies [Line Items]
Number of presale agreements | agreement		2
Estimated development costs		$ 107,300,000
Scenario, Forecast | Core Transaction | AMERICAN CAMPUS COMMUNITIES OPERATING PARTNERSHIP, L.P. | Consolidated properties
Loss Contingencies [Line Items]
Asset acquisition, consideration transferred			$ 46,900,000

Segments - Narrative (Details)

Segments - Narrative (Details)	9 Months Ended
	Sep. 30, 2018Segment
Segment Reporting [Abstract]
Identified reportable segments (segments)	4

Segments - Schedule of Segment

Segments - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 213,469	$ 196,938	$ 634,937	$ 568,884
Ground/facility lease expense	(2,951)	(2,329)	(8,526)	(7,151)
Interest expense	(25,185)	(18,654)	(72,207)	(47,944)
Depreciation and amortization	(67,247)	(62,271)	(199,191)	(172,588)
Operating expenses	(191,968)	(179,363)	(532,176)	(489,480)
Total consolidated revenues, including interest income	214,743	198,197	638,677	572,607
Segment operating income before depreciation and amortization	21,501	17,575	102,761	79,404
Gain (loss) from disposition of real estate	0	0	42,314	(632)
Other operating and nonoperating income	570	0	3,218	0
Loss from early extinguishment of debt	0	0	(784)	0
Provision for real estate impairment	0	0	0	(15,317)
Income tax provision	219	(267)	(2,147)	(791)
Net (loss) income	(2,737)	(1,233)	69,503	30,563
Operating segments
Segment Reporting Information [Line Items]
Total revenues	213,894	197,347	636,188	570,092
Segment operating income before depreciation and amortization	88,336	84,941	310,051	285,339
Net (loss) income	(2,737)	(1,233)	69,503	30,563
Operating segments | Owned properties
Segment Reporting Information [Line Items]
Rental revenues and other income	203,526	184,282	600,138	533,866
Interest income	382	385	1,146	1,161
Total revenues	203,908	184,667	601,284	535,027
Operating expenses before depreciation, amortization, and ground/facility lease expense	(107,997)	(99,423)	(282,193)	(249,552)
Ground/facility lease expense	(2,306)	(1,877)	(6,293)	(5,163)
Interest expense	(5,622)	(1,540)	(9,011)	(1,194)
Operating income before depreciation and amortization	87,983	81,827	303,787	279,118
Depreciation and amortization	62,909	58,339	185,171	161,341
Capital expenditures	144,910	196,910	428,065	473,638
Operating segments | On-campus participating properties
Segment Reporting Information [Line Items]
Rental revenues and other income	6,980	6,799	23,605	23,128
Interest income	43	24	105	47
Total revenues	7,023	6,823	23,710	23,175
Operating expenses before depreciation, amortization, and ground/facility lease expense	(3,875)	(3,923)	(11,030)	(11,080)
Ground/facility lease expense	(645)	(452)	(2,233)	(1,988)
Interest expense	(1,282)	(1,312)	(3,804)	(3,987)
Operating income before depreciation and amortization	1,221	1,136	6,643	6,120
Depreciation and amortization	1,962	1,892	5,856	5,621
Capital expenditures	1,394	2,039	2,918	2,909
Operating segments | Third-party development services
Segment Reporting Information [Line Items]
Operating income before depreciation and amortization	(1,221)	1,452	(2,093)	(1,274)
Development and construction management fees	835	3,566	3,883	4,697
Operating expenses	(2,056)	(2,114)	(5,976)	(5,971)
Operating segments | Property management services
Segment Reporting Information [Line Items]
Operating income before depreciation and amortization	353	526	1,714	1,375
Operating expenses	(1,775)	(1,765)	(5,597)	(5,818)
Unallocated
Segment Reporting Information [Line Items]
Total revenues	849	850	2,489	2,515
Operating expenses	(24,615)	(23,636)	(83,958)	(65,448)
Property management fees from external customers | Operating segments | Property management services
Segment Reporting Information [Line Items]
Total revenues	$ 2,128	$ 2,291	$ 7,311	$ 7,193

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 31, 2018	Oct. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Asset acquisition, consideration transferred						$ 302,300
Pay-off of mortgage and construction loans					$ 146,165	99,185
Subsequent Event | Dividend Declared
Subsequent Event [Line Items]
Distributions declared per common unit (in dollars per unit)	$ 0.46
Core Transaction
Subsequent Event [Line Items]
Asset acquisition, consideration transferred			$ 83,700	$ 306,000		$ 146,100
Core Transaction | Subsequent Event
Subsequent Event [Line Items]
Asset acquisition, consideration transferred		$ 46,900
Pay-off of mortgage and construction loans		$ 40,200