Earnings Per Common Share - Details of Earnings Per Share Calculations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income - continuing operations	$ 13,657	$ 3,526
Net income (loss) - discontinued operations	(23)	(16)
Net income	$ 13,634us-gaap_NetIncomeLoss	$ 3,510us-gaap_NetIncomeLoss
Weighted average common shares outstanding
Basic	39,527	39,272
Incremental shares with dilutive effect:
Diluted	39,660	39,389
Basic income (loss) per share
Continuing operations	$ 0.34	$ 0.09
Discontinued operations	$ 0.00	$ 0.00
Total net income per share	$ 0.34us-gaap_EarningsPerShareBasic	$ 0.09us-gaap_EarningsPerShareBasic
Diluted income (loss) per share
Continuing operations	$ 0.34	$ 0.09
Discontinued operations	$ 0.00	$ 0.00
Total net income per share	$ 0.34us-gaap_EarningsPerShareDiluted	$ 0.09us-gaap_EarningsPerShareDiluted
Restricted Stock [Member]
Incremental shares with dilutive effect:
Stock options	133	117

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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 amount of net income (loss) derived from continuing operations during 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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