Income Taxes - Schedule of Income Tax Expense as Percentage of Pre-Tax Earnings (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income taxes at statutory rate (percent)	35.00%	35.00%	35.00%
Valuation allowance on foreign tax credits (percent)	(12.00%)	(33.00%)	0.00%
Valuation allowance on state net operating loss carryforwards (percent)	(2.00%)	(19.00%)	0.00%
Valuation allowance reversal- investment in foreign entity (percent)		0.00%	(1.00%)
Valuation Allowance – Other (percent)	(3.00%)	0.00%	0.00%
Change in tax rate on deferred items (percent)	0.00%	18.00%	3.00%
Tax reform – Impact of change in tax rate (percent)	96.00%	0.00%	0.00%
State income taxes, net of federal benefit (percent)	3.00%	5.00%	0.00%
Other items - net (percent)	(2.00%)	(4.00%)	1.00%
Total (percent)	115.00%	2.00%	38.00%
Increase (decrease) in taxes resulting from:
Income taxes at statutory rate	$ (18,004)	$ (9,502)	$ 15,140
Valuation allowance on foreign tax credits	6,145	8,991	0
Valuation allowance on state net operating loss carryforwards	868	5,028	0
Valuation allowance reversal- investment in foreign entity	0	0	(456)
Valuation Allowance - Other	1,353	0	0
Change in tax rate on deferred items	0	(4,772)	1,078
Tax reform – Impact of change in tax rate	(49,219)	0	0
State income taxes, net of federal benefit	(1,386)	(1,384)	146
Other items - net	1,270	1,170	424
Total	$ (58,973)	$ (469)	$ 16,332

Effective Income Tax Rate Reconciliation, Effect of Change in Enacted Tax Rate on Deferred Items, Amount

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Effective Income Tax Rate Reconciliation Foreign Tax Credit Valuation Allowance

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Increase Decrease In Taxes [Abstract]

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