Income Taxes

The following table presents income tax expense and the effective tax rate:



	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
	(Dollars in thousands)
Income tax expense	$	30,652		$	26,449		$	59,079		$	56,742
Effective tax rate	25		%	21		%	25		%	23		%

The effective tax rate for the three and six months ended June 30, 2015 and 2014 is lower than the statutory federal rate of 35% primarily due to tax benefits from foreign income taxed at lower rates, partially offset by state income taxes and non-deductible stock-based compensation. During the three months ended June 30, 2014, the Company recognized a discrete tax benefit of $5.2 million due to changes in estimates of U.S. income taxes related to the 2013 worthless stock deduction and the 2014 repatriation of earnings from foreign subsidiaries.

Current deferred tax liabilities and Other long-term tax liabilities as of June 30, 2015 reflect the use of a portion of U.S. foreign tax credits during the first half of 2015, an increase in the deferred tax liability related to the Subordinated Convertible Debentures, and the reclassification of unrecognized tax benefits.