Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 22,049	$ 7,976	$ 48,197	$ 26,961
Less: Income distributed to participating securities	(507)	(175)	(1,091)	(523)
Less: Undistributed income allocable to participating securities	(1,719)		(2,518)
Net income available to common stockholders	$ 19,823	$ 7,801	$ 44,588	$ 26,438
Weighted average common shares (in thousands)	150,892	134,709	145,149	134,552
Basic earnings per share	$ 0.13	$ 0.06	$ 0.31	$ 0.20
Net income	$ 22,049	$ 7,976	$ 48,197	$ 26,961
Weighted average common shares	150,892	134,709	145,149	134,552
Dilutive effect of common stock equivalents	9,730	1,224	10,435	1,216
Weighted average diluted shares	166,622	135,933	155,584	135,768
Diluted earnings per share	$ 0.13	$ 0.06	$ 0.31	$ 0.20

The total amount of dividends declared in the period for each class of stock and the contractual amount of dividends (or interest on participating income bonds) that must be paid for the period (for example, unpaid cumulative dividends). Dividends declared in the current period do not include dividends declared in respect of prior-period unpaid cumulative dividends. Preferred dividends that are cumulative only if earned are deducted only to the extent that they are earned.

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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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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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