CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Cloud and related solutions	$ 651,010	$ 606,936	$ 577,410
Software and services	62,892	79,400	93,678
Maintenance	75,680	74,622	81,432
Total revenues	789,582	760,958	752,520
Cost of revenues (exclusive of depreciation, shown separately below):
Cloud and related solutions	315,006	282,952	270,715
Software and services	39,018	49,202	68,597
Maintenance	40,787	42,993	40,429
Total cost of revenues	394,811	375,147	379,741
Other operating expenses:
Research and development	113,215	98,683	101,950
Selling, general and administrative	153,695	140,467	139,839
Depreciation	13,380	13,616	14,776
Restructuring and reorganization charges	8,796	416	3,074
Total operating expenses	683,897	628,329	639,380
Operating income	105,685	132,629	113,140
Other income (expense):
Interest expense	(16,794)	(16,262)	(10,967)
Amortization of original issue discount	(2,790)	(4,866)	(6,246)
Interest and investment income, net	3,246	2,457	1,038
Loss on repurchase of convertible notes		(8,651)
Other, net	(1,637)	(5,308)	(624)
Total other	(17,975)	(32,630)	(16,799)
Income before income taxes	87,710	99,999	96,341
Income tax provision	(26,346)	(37,117)	(33,774)
Net income	$ 61,364	$ 62,882	$ 62,567
Weighted-average shares outstanding:
Basic	32,415	30,968	31,051
Diluted	32,865	33,014	33,438
Earnings per common share:
Basic	$ 1.89	$ 2.03	$ 2.01
Diluted	$ 1.87	$ 1.90	$ 1.87