Net Income (Loss) per Share - Earnings Attributable to Common Shareholders and Weighted Average Common Shares Outstanding (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Continuing operations
Consolidated net income (loss)									$ 6,301	$ 77,044	$ (26,241)
Less: Net (income) attributable to noncontrolling interest									(2,078)	(1,531)	(676)
Earnings (loss) available for diluted earnings per share									4,223	75,513	(26,917)
Less: Undistributed net income from continuing operations allocated to participating securities									0	(13,493)	0
Earnings (loss) from continuing operations available to common shareholders for basic earnings per share									4,223	62,020	(26,917)
Discontinued operations
Net income (loss) from discontinued operations available for diluted earnings per share	$ 7,191	$ 37,193	$ 1,229	$ 418	$ 563	$ (7,164)	$ (2,048)	$ (8,216)	46,031	(16,865)	(186,130)
Less: Undistributed net income from discontinued operations allocated to participating securities									0	3,014	0
Earnings (loss) from discontinued operations available to common shareholders for basic earnings per share									$ 46,031	$ (13,851)	$ (186,130)
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average common shares outstanding - basic									42,143	34,546	34,266
Weighted average common shares upon conversion of participating securities									0	7,515	0
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements									238	273	0
Weighted average common shares outstanding - diluted									42,381	42,334	34,266
Anti-dilutive awards excluded from diluted weighted average shares outstanding									1,093	2,102	10,864