Equity and Earnings (Loss) per Share (Detail) - Reclassification out of Accumulated Other Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	$ (3,267)	$ 1,169	$ (86)	$ (81)	$ 758	$ (19)	$ (25)	$ 0	$ (2,265)	$ 714
Net income (loss) from continuing operations attributable to common shareholders									22,843	(5,807)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss) from continuing operations attributable to common shareholders									689
Pension Plan Items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Recognized net actuarial loss									20
Settlement loss									50
Total before tax									70
Income tax expense (benefit)									(155)
Net income (loss) from continuing operations attributable to common shareholders									(85)
Post Employment Benefit Items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Recognized net actuarial loss									18
Amortization of prior service cost									(369)
Plan amendment and curtailment									1,183
Recognition of prior service cost due to curtailment									(52)
Total before tax									780
Income tax expense (benefit)									(6)
Net income (loss) from continuing operations attributable to common shareholders									$ 774