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

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Derivative Financial Instruments - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) counterparty	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Derivative [Line Items]
Notional Amount	$ 5,911,385	$ 6,644,081
Net unrealized gain on interest rate agreements	8,908	1,022	$ 3,271
Stockholders' equity attributable to parent	$ 1,348,794	1,212,287	1,149,428	$ 1,146,265
Number of counterparties \| counterparty	2
Net Unrealized Losses on Interest Rate Agreements Accounted for as Cash Flow Hedges
Derivative [Line Items]
Stockholders' equity attributable to parent	$ (34,045)	(42,953)	(44,020)
Derivative Liabilities
Derivative [Line Items]
Notional Amount	2,953,724	3,485,466
Mortgage Banking Activities, Net
Derivative [Line Items]
Changes in fair value of assets	57,000	51,844	36,445
Loan purchase commitments \| Mortgage Banking Activities, Net
Derivative [Line Items]
Changes in fair value of assets	(1,336)	37,880	25,613
Interest Rate Contract
Derivative [Line Items]
Notional Amount	3,850,000	3,210,000
TBAs
Derivative [Line Items]
Notional Amount	1,460,000	1,700,000
TBAs \| Derivative Liabilities
Derivative [Line Items]
Notional Amount	935,000	1,400,000
Futures
Derivative [Line Items]
Notional Amount		8,000
Residential and Commercial Loans
Derivative [Line Items]
Valuation adjustments on derivatives	40,000	(31,000)	$ 10,000
Interest rate agreements \| Cash Flow Hedging
Derivative [Line Items]
Net unrealized gain on interest rate agreements	9,000	1,000
Interest rate agreements \| Derivative Liabilities
Derivative [Line Items]
Notional Amount	1,742,000	1,248,000
Interest rate agreements \| Derivative Liabilities \| Cash Flow Hedging
Derivative [Line Items]
Notional Amount	$ 139,500	$ 139,500