TWO Quarterly report pursuant to Section 13 or 15(d)

Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	$ 21,263,618	$ 21,501,250
Available-for-sale Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	19,955,664	19,780,175
Servicing Contracts [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	688,078	424,740
Cash and Cash Equivalents [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	0	15,000
Restricted Cash and Cash Equivalents [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	456,453	417,018
Due From Correspondent Brokers [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	81,860	773,422
Derivative Financial Instruments, Assets [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets pledged or restricted as collateral for repurchase agreements	$ 81,563	$ 90,895