Condensed Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Revenues	$ 306,408	$ 299,288
Costs and expenses:
Cost of revenues	45,504	48,152
Sales and marketing	10,519	17,275
Research and development	16,132	15,375
General and administrative	34,001	33,067
Total costs and expenses	106,156	113,869
Operating income	200,252	185,419
Interest expense	(22,631)	(40,788)
Non-operating income (loss), net	12,203	7,804
Income before income taxes	189,824	152,435
Income tax expense	(27,297)	(18,172)
Net Income	162,527	134,263
Other comprehensive income (loss)	49	243
Comprehensive Income	$ 162,576	$ 134,506
Basic income (loss) per share
Net Income	$ 1.36	$ 1.38
Diluted income (loss) per share
Net Income	$ 1.35	$ 1.09
Shares used to compute net income per share
Basic	119,757	97,250
Diluted	120,317	123,506

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e557-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669625-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669619-108580