Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Investment properties:
Land and improvements	$ 189,759				$ 130,788
Building and improvements	2,402,643				1,284,863
Tenant improvements	14,133				9,243
Acquired lease intangibles	301,462				205,168
Gross real estate property	2,907,997				1,630,062
Accumulated depreciation	(181,785)				(91,250)
Net real estate property	2,726,212				1,538,812
Real estate loans receivable	39,154				39,349
Investment in unconsolidated entity	2,258				1,322
Net real estate investments	2,767,624				1,579,483
Cash and cash equivalents	15,491				3,143				$ 15,923
Tenant receivables, net	9,790				2,977
Other assets	95,187				53,283
Total assets	2,888,092				1,638,886
Liabilities:
Credit facility	643,742				389,375
Notes payable	224,330				0
Mortgage debt	123,083				94,240
Accounts payable	4,423				644
Dividends and distributions payable	32,179				20,783
Accrued expenses and other liabilities	42,287				24,473
Acquired lease intangibles, net	9,253				5,950
Total liabilities	1,079,297				535,465
Redeemable noncontrolling interest – Series A Preferred Units and partially owned properties	26,477				26,960
Equity:
Common shares, $0.01 par value, 500,000,000 common shares authorized, 135,966,013 and 86,864,063 common shares issued and outstanding as of December 31, 2016 and December 31, 2015, respectively	1,362				872
Additional paid-in capital	1,920,642				1,129,284
Accumulated deficit	(197,261)				(109,024)
Noncontrolling interests:
Operating Partnership	43,142				45,451
Partially owned properties	725				9,878
Total noncontrolling interests	43,867				55,329
Total equity	1,782,318				1,076,461				569,209
Capital:
Accumulated other comprehensive income	13,708				0
Total liabilities and equity	2,888,092				1,638,886
Stockholders' Equity Attributable to Parent	1,738,451				1,021,132
Operating Partnership
Investment properties:
Land and improvements	189,759	$ 172,685	$ 160,718	$ 141,152	130,788	$ 123,240	$ 110,349	$ 99,950	79,334
Building and improvements	2,402,643	2,220,448	2,080,192	1,452,885	1,284,863	1,167,768	931,467	817,673	644,086
Tenant improvements	14,133	12,627	11,519	10,455	9,243	8,524	6,810	6,417	5,614
Acquired lease intangibles	301,462	282,798	263,919	228,788	205,168	176,087	132,255	109,173	72,985
Gross real estate property	2,907,997	2,688,558	2,516,348	1,833,280	1,630,062	1,475,619	1,180,881	1,033,213	802,019
Accumulated depreciation	(181,785)	(153,815)	(129,136)	(108,239)	(91,250)	(75,930)	(64,353)	(53,451)	(45,569)
Net real estate property	2,726,212	2,534,743	2,387,212	1,725,041	1,538,812	1,399,689	1,116,528	979,762	756,450
Real estate loans receivable	39,154	43,817	38,774	35,937	39,349	28,979	25,320	16,094	15,876
Investment in unconsolidated entity	2,258	1,326	1,354	1,327	1,322	1,323	1,324	1,324	1,324
Net real estate investments	2,767,624	2,579,886	2,427,340	1,762,305	1,579,483	1,429,991	1,143,172	997,180	773,650
Cash and cash equivalents	15,491	8,396	37,945	22,906	3,143	4,718	22,549	35,774	15,923
Tenant receivables, net	9,790	9,551	3,427	6,024	2,977	3,047	2,333	2,127	1,324
Other assets	95,187	72,814	64,200	59,657	53,283	34,741	31,598	27,142	16,423
Total assets	2,888,092	2,670,647	2,532,912	1,850,892	1,638,886	1,472,497	1,199,652	1,062,223	807,320
Liabilities:
Credit facility	643,742	448,321	369,685	115,789	389,375	467,072	187,638	69,384	134,144
Notes payable	224,330	224,339	149,561	149,551	0
Mortgage debt	123,083	113,736	114,296	114,816	94,240	94,795	95,332	83,584	77,708
Accounts payable	4,423	2,222	1,723	1,659	644	1,393	1,097	448	700
Dividends and distributions payable	32,179	31,755	31,771	25,701	20,783	17,059	16,942	16,722	16,548
Accrued expenses and other liabilities	42,287	46,574	38,593	28,948	24,473	19,038	14,997	13,029	6,140
Acquired lease intangibles, net	9,253	9,399	9,348	6,407	5,950	5,053	3,171	3,056	2,871
Total liabilities	1,079,297	876,346	714,977	442,871	535,465	604,410	319,177	186,223	238,111
Redeemable noncontrolling interest – Series A Preferred Units and partially owned properties	26,477	25,891	19,867	27,065	26,960	11,719	11,656	13,721	0
Capital:
General partner’s capital, 134,620,300 and 86,864,063 units issued and outstanding as of September 31, 2016 and December 31, 2015, respectively	1,724,743	1,720,867	1,738,121	1,323,251	1,021,132	811,282	823,032	818,634	534,730
Limited partners’ capital, 3,618,988 and 3,879,115 units issued and outstanding as of September 31, 2016 and December 31, 2015, respectively	43,142	46,138	50,155	47,567	45,451	43,737	44,473	42,430	33,727
Accumulated other comprehensive income	13,708	652			0
Total partners’ capital	1,781,593	1,767,657	1,788,276	1,370,818	1,066,583	855,019	867,505	861,064	568,457
Noncontrolling interests - partially owned properties	725				9,878
Total capital	1,782,318	1,768,410	1,798,068	1,380,956	1,076,461	856,368	868,819	862,279	569,209
Total liabilities and equity	$ 2,888,092	2,670,647	2,532,912	1,850,892	1,638,886	1,472,497	1,199,652	1,062,223	807,320
Partially Owned Properties | Operating Partnership
Capital:
Noncontrolling interests - partially owned properties		$ 753	$ 9,792	$ 10,138	$ 9,878	$ 1,349	$ 1,314	$ 1,215	$ 752