Reconciliation of Income Tax Expense With Expected Amounts Based Upon Statutory Federal Tax Rates (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments, Owned, Federal Income Tax Note [Line Items]
Expected federal income tax at statutory rate	$ (4,687)	$ 33,668	$ 34,896
State income taxes before valuation allowance, net of federal tax effect	(2,115)	(357)	440
Income (losses) without tax expense (benefit)	(72)	22	(40)
Effect of foreign source income	(19,996)	(10,583)	(5,314)
Tax contingencies	1,379	1,383	1,374
Valuation allowance	2,106	445	358
Nondeductible acquisition costs	2,176	0	0
U.S. federal research credit	(2,085)	(3,233)	(790)
Other items, net	1,722	324	(43)
Income tax (benefit) expense	$ (21,572)	$ 21,669	$ 30,881