Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income (loss)	$ 14,146us-gaap_NetIncomeLoss	$ (8,441)us-gaap_NetIncomeLoss
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Premium amortization and (discount accretion) on Mortgage-backed securities, other securities and whole-loans, net	2,582	3,223
Restricted stock amortization expense	679us-gaap_RestrictedStockExpense	588us-gaap_RestrictedStockExpense
Premium amortization for MAC interest rate swaps	(371)
Interest payments and basis recovered on MAC interest rate swaps	246
Premium on purchase of Residential whole-loans	(230)
Unrealized gain (loss) on Mortgage-backed securities and other securities and whole-loans, net	(28,410)us-gaap_UnrealizedGainLossOnSecurities	(31,091)us-gaap_UnrealizedGainLossOnSecurities
Mark-to-market adjustments on linked transactions		(104)
Mark-to-market adjustments on derivative instruments	56,037us-gaap_UnrealizedGainLossOnDerivatives	56,390us-gaap_UnrealizedGainLossOnDerivatives
Other loss on Mortgage-backed securities and other securities	4,651	1,709
Realized gain on sale of Mortgage-backed securities and other securities, net	(7,468)	(3,716)
Realized loss on sale of Interest-Only Strips accounted for as derivatives, net	2	869
Realized gain on sale of TBAs, net	(7,448)	(2,370)
Realized gain on sale of swaptions, net	(713)wmc_RealizedGainLossOnSaleOfSwaptions
Realized gain on forward contracts	(646)
Realized gain on linked transaction, net		(1,290)wmc_RealizedGainLossOnLinkedTransaction
Gain on foreign currency transactions, net	(2,396)
Changes in operating assets and liabilities:
Increase in accrued interest receivable	(4,533)	(2,263)
Decrease in other assets	155	101
Decrease in accrued interest payable	(1,247)	(2,236)
Increase (decrease) in accounts payable and accrued expenses	841	(21)
Increase in payable to related party	178	164
Net cash provided by operating activities	26,055	11,512
Cash flows from investing activities:
Purchase of Mortgage-backed securities and other securities	(334,429)	(371,178)
Proceeds from sale of Mortgage-backed securities and other securities	536,869	114,021
Principal payments and basis recovered on Mortgage-backed securities and other securities	100,436	55,483
Principal payments and basis recovered on securities underlying linked transactions		3,018
Purchase of Residential Whole-Loans	(10,230)
Principal payments on Residential Whole-Loans	20
Purchase of Commercial Whole-Loan	(8,750)wmc_PurchaseOfCommercialWholeLoans
Net settlements of TBAs	9,629	2,370
Proceeds from sale of interest rate swaptions	17,768
Interest payments and basis recovered on MAC interest rate swaps	(32)
Proceeds from (payments made) on reverse repurchase agreements, net	(65,674)
Premium for interest rate swaptions, net	(19,215)
Net cash provided by (used in) investing activities	226,392	(196,286)
Cash flows from financing activities:
Proceeds from repurchase agreement borrowings	5,074,942	4,330,593
Proceeds from repurchase agreement borrowings underlying linked transactions		38,571
Repayments of repurchase agreement borrowings	(5,331,410)	(4,086,699)
Repayments of repurchase agreement borrowings underlying linked transactions		(87,044)
Proceeds from forward contracts	71,417
Repayments of forward contracts	(70,771)
Interest payments and basis recovered on MAC interest rate swaps containing an other-than-insignificant financing element	(214)
Due from counterparties, net	(51,435)	(2,387)
Due to counterparties, net	62,373wmc_IncreaseDecreaseDueToCounterparties	(31,848)wmc_IncreaseDecreaseDueToCounterparties
Dividends on common stock	(29,204)us-gaap_PaymentsOfDividends	(19,445)us-gaap_PaymentsOfDividends
Net cash provided by (used in) financing activities	(274,302)	141,741
Effect of exchange rate changes on cash and cash equivalents	115
Net increase (decrease) in cash and cash equivalents	(21,740)	(43,033)
Cash and cash equivalents beginning of period	47,222	48,525
Cash and cash equivalents end of period	25,482	5,492
Supplemental disclosure of operating cash flow information:
Interest paid	6,560us-gaap_InterestPaid	3,275us-gaap_InterestPaid
Supplemental disclosure of non-cash financing/investing activities:
Principal payments of Mortgage-backed securities and other securities, not settled	290	114
Mortgage-backed securities and other securities sold, not settled		2,442
Mortgage-backed securities and other securities purchased, not settled		(104,526)
Mortgage-backed securities recorded upon unlinking of linked transactions		(62,435)
Net unsettled TBAs	4
Deferred offering costs payable		145us-gaap_DeferredOfferingCosts
Dividends and distributions declared, not paid	$ 28,086	$ 18,136

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.

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