Quarterly Financial Results (unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Schedule of Unaudited Quarterly Financial Results

(in thousands, except per share data)	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
Year ended December 31, 2015:
Revenue	$	526,536	$	540,723	$	551,030	$	579,159
Cost of revenue (exclusive of amortization of acquired intangible assets)	169,294		179,910		183,204		193,212
Net income	77,746		67,200		88,040		88,420
Basic net income per share	0.44		0.38		0.49		0.50
Diluted net income per share	0.43		0.37		0.49		0.49
Year ended December 31, 2014:
Revenue	$	453,502	$	476,035	$	498,042	$	536,295
Cost of revenue (exclusive of amortization of acquired intangible assets)	139,612		149,318		158,812		163,201
Net income	72,800		72,886		91,155		97,107
Basic net income per share	0.41		0.41		0.51		0.55
Diluted net income per share	0.40		0.40		0.50		0.54