Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageRemainingMaturity1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Average variable interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageVariableInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	two_DerivativeByMaturityAxis=two_DerivativeMaturityWithinOneYearFromBalanceSheetDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	two_DerivativeByMaturityAxis=two_DerivativeMaturityOverOneAndWithinTwoYearsFromBalanceSheetDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	two_DerivativeByMaturityAxis=two_DerivativeMaturityOverTwoAndWithinThreeYearsFromBalanceSheetDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	two_DerivativeByMaturityAxis=two_DerivativeMaturityOverThreeAndWithinFourYearsFromBalanceSheetDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	two_DerivativeByMaturityAxis=two_DerivativeMaturityOverFourYearsFromBalanceSheetDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=two_ForwardStartingInterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swap Payers (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Notional	$ 24,113,321,000	$ 18,802,500,000	$ 16,988,116,000	$ 22,062,904,000	$ 26,141,370,000	$ 21,998,381,000
Interest Rate Swap [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 15,611,201,000	$ 15,307,063,000
Weighted Average Fixed Interest Rate	1.509%	1.441%
Weighted Average Variable Interest Rate	1.317%	0.943%
Weighted Average Remaining Maturity	3 years 6 months 27 days	3 years 2 months 26 days
Interest Rate Swap [Member] \| Derivative Maturity Within One Year From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 875,000,000	$ 2,375,000,000
Weighted Average Fixed Interest Rate	0.721%	0.765%
Weighted Average Variable Interest Rate	1.322%	0.934%
Weighted Average Remaining Maturity	2 months 4 days	7 months 3 days
Interest Rate Swap [Member] \| Derivative Maturity Over One And Within Two Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 4,320,000,000	$ 5,340,000,000
Weighted Average Fixed Interest Rate	1.155%	1.232%
Weighted Average Variable Interest Rate	1.314%	0.945%
Weighted Average Remaining Maturity	9 months 1 day	1 year 7 months 2 days
Interest Rate Swap [Member] \| Derivative Maturity Over Two And Within Three Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 1,020,000,000	$ 350,000,000
Weighted Average Fixed Interest Rate	1.524%	1.283%
Weighted Average Variable Interest Rate	1.313%	0.895%
Weighted Average Remaining Maturity	1 year 9 months 22 days	2 years 5 months 9 days
Interest Rate Swap [Member] \| Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 1,590,000,000	$ 1,460,000,000
Weighted Average Fixed Interest Rate	1.542%	1.481%
Weighted Average Variable Interest Rate	1.311%	0.92%
Weighted Average Remaining Maturity	2 years 11 months 17 days	3 years 8 months 26 days
Interest Rate Swap [Member] \| Derivative Maturity Over Four Years From Balance Sheet Date [Member] \| Long [Member]
Derivative [Line Items]
Notional	$ 7,806,201,000	$ 5,782,063,000
Weighted Average Fixed Interest Rate	1.793%	1.984%
Weighted Average Variable Interest Rate	1.321%	0.955%
Weighted Average Remaining Maturity	5 years 11 months 5 days	6 years 2 months
Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Notional	$ 200,000,000	$ 777,063,000
Weighted Average Fixed Interest Rate	2.70%	2.00%