Equity - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Equity [Abstract]
Net income attributable to Redwood	$ 12,063	$ 14,801
Less: Dividends and undistributed earnings allocated to participating securities	(701)	(822)
Net income allocated to common shareholders	$ 11,362	$ 13,979
Basic weighted average common shares outstanding (shares)	77,137,682	83,360,312
Basic earnings per common share (usd per share)	$ 0.15	$ 0.17
Less: Dividends and undistributed earnings allocated to participating securities	$ (701)	$ (822)
Net income allocated to common shareholders	$ 11,362	$ 13,979
Net effect of dilutive equity awards (in shares)	0	2,261,904
Diluted weighted average common shares outstanding (shares)	77,137,682	85,622,216
Diluted earnings per common share (usd per share)	$ 0.15	$ 0.16

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the diluted earnings (loss) per share or per unit calculation under the two-class method.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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