Combined Consolidated Statements of Income - USD ($) $ in Thousands									3 Months Ended								11 Months Ended	12 Months Ended
	Dec. 02, 2016	Sep. 01, 2016	Jun. 01, 2016	Mar. 01, 2016	Dec. 01, 2015	Sep. 01, 2015	Jun. 08, 2015	Mar. 12, 2015	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	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net interest income
Interest income									$ 60,721	$ 60,284	$ 55,766	$ 59,601	$ 62,903	$ 63,013	$ 59,239	$ 56,384		$ 236,372	$ 241,539	$ 187,325
Interest expense																		120,827	113,303	77,574
Net interest income																		115,545	128,236	109,751
Provision for loan losses																		300	600	600
Net interest income after provision for loan losses									28,517	29,599	27,214	29,915	33,297	33,328	31,602	29,409		115,245	127,636	109,151
Other income
Operating lease income																		77,277	80,465	56,649
Tenant recoveries																		5,958	9,907	9,183
Sale of loans, net																		26,009	71,066	145,275
Realized gain (loss) on securities																		7,724	24,007	26,977
Unrealized gain (loss) on Agency interest-only securities																		(56)	(1,249)	2,144
Realized gain on sale of real estate, net																		20,636	40,386	29,760
Fee and other income																		21,365	15,205	11,704
Net result from derivative transactions																		(1,409)	(38,937)	(94,798)
Earnings (loss) from investment in unconsolidated joint ventures																		426	371	1,990
Gain on assignment of mortgage loan financing																		0	0	432
Gain (loss) on extinguishment of debt																		5,382	0	(150)
Total other income																		163,312	201,221	189,166
Costs and expenses
Salaries and employee benefits																		64,270	61,612	82,144
Operating expenses																		20,552	25,103	25,398
Real estate operating expenses																		29,953	35,886	32,670
Real estate acquisition costs																		592	1,983	2,404
Fee expense																		3,703	4,521	3,023
Depreciation and amortization																		39,447	39,061	28,447
Total costs and expenses									45,335	40,615	37,405	35,162	38,347	42,260	44,180	43,379		158,517	168,166	174,086
Income (loss) before taxes									72,394	58,319	1,644	(12,317)	67,133	(1,383)	73,874	21,067		120,040	160,691	124,231
Income tax expense (benefit)									773	8,721	(2,301)	(873)	10,457	(4,181)	5,177	3,104		6,320	14,557	26,605
Net income (loss)									71,621	49,598	3,945	(11,444)	56,676	2,798	68,697	17,963		113,720	146,134	97,626
Net (income) loss attributable to noncontrolling interest in consolidated joint ventures									(298)	439	(235)	232	(2,146)	85	684	(191)		138	(1,568)	370
Pre-IPO net loss attributable to predecessor unitholders																		0	0	12,628
Net (income) loss attributable to noncontrolling interest in operating partnership									(29,467)	(22,429)	(908)	5,673	(27,407)	430	(35,171)	(8,597)		(47,131)	(70,745)	(66,437)
Net income (loss) attributable to Class A common shareholders									$ 41,856	$ 27,608	$ 2,802	$ (5,539)	$ 27,123	$ 3,313	$ 34,210	$ 9,175		$ 66,727	$ 73,821	$ 44,187
Earnings per share:
Basic (in dollars per share)									$ 0.64	$ 0.44	$ 0.05	$ (0.09)	$ 0.51	$ 0.06	$ 0.68	$ 0.18		$ 1.08	$ 1.43	$ 0.90
Diluted (in dollars per share)									0.63	0.44	0.05	(0.09)	0.50	0.06	0.67	0.15		$ 1.06	$ 1.42	$ 0.86
Weighted average shares outstanding:
Basic (in shares)																	49,296,417	61,998,089	51,702,188	49,296,417
Diluted (in shares)																	97,583,310	107,638,788	51,870,808	97,583,310
Dividends per share of Class A common stock (in dollars per share)									$ 0.460	$ 0.275	$ 0.275	$ 0.275	$ 1.450	$ 0.275	$ 0.250	$ 0.250
Class A Common Stock
Costs and expenses
Net income (loss) attributable to Class A common shareholders																	$ 44,187	$ 66,727	$ 73,821	$ 44,187
Earnings per share:
Basic (in dollars per share)																	$ 0.90	$ 1.08	$ 1.43
Diluted (in dollars per share)																	$ 0.86	$ 1.06	$ 1.42
Weighted average shares outstanding:
Basic (in shares)																	49,296,417	61,998,089	51,702,188
Diluted (in shares)																	97,583,310	107,638,788	51,870,808
Dividends per share of Class A common stock (in dollars per share)	$ 0.460	$ 0.275	$ 0.275	$ 0.275	$ 1.450	$ 0.275	$ 0.250	$ 0.250										$ 1.285	$ 2.225	$ 0