Two Harbors Investment Corp. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Payers (Details)

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Payers (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional	$ 41,330,283,000	$ 31,226,878,000	$ 28,618,861,000	$ 24,113,321,000	$ 16,988,116,000	$ 18,802,500,000
Interest Rate Swap [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 23,401,328,000	$ 22,920,135,000
Weighted Average Fixed Interest Rate	1.876%	1.694%
Weighted Average Variable Interest Rate	2.343%	1.493%
Weighted Average Remaining Maturity	3 years 9 months 7 days	3 years 3 days
Interest Rate Swap [Member] \| Derivative Maturity Within One Year From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 1,000,000,000	$ 4,320,000,000
Weighted Average Fixed Interest Rate	1.008%	1.155%
Weighted Average Variable Interest Rate	2.336%	1.508%
Weighted Average Remaining Maturity	0 days	15 days
Interest Rate Swap [Member] \| Derivative Maturity Over One And Within Two Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 4,336,897,000	$ 5,448,135,000
Weighted Average Fixed Interest Rate	1.769%	1.767%
Weighted Average Variable Interest Rate	2.336%	1.386%
Weighted Average Remaining Maturity	1 year 14 days	1 year 9 months 14 days
Interest Rate Swap [Member] \| Derivative Maturity Over Two And Within Three Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 5,140,000,000	$ 5,490,000,000
Weighted Average Fixed Interest Rate	1.705%	1.945%
Weighted Average Variable Interest Rate	2.334%	1.509%
Weighted Average Remaining Maturity	2 years 25 days	2 years 10 months 13 days
Interest Rate Swap [Member] \| Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 4,117,000,000	$ 2,417,000,000
Weighted Average Fixed Interest Rate	1.55%	1.788%
Weighted Average Variable Interest Rate	2.362%	1.628%
Weighted Average Remaining Maturity	2 years 11 months 8 days	3 years 11 months 1 day
Interest Rate Swap [Member] \| Derivative Maturity Over Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 8,807,431,000	$ 5,245,000,000
Weighted Average Fixed Interest Rate	2.309%	1.764%
Weighted Average Variable Interest Rate	2.343%	1.516%
Weighted Average Remaining Maturity	7 years 1 month 20 days	6 years 5 months 8 days
Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Notional	$ 567,800,000	$ 570,000,000.0
Weighted Average Fixed Interest Rate	2.80%	2.10%