Unrestricted Subsidiaries (Financial Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and cash equivalents	$ 123,950	$ 255,530	$ 433,663	$ 207,801
Accounts receivable	199,871	114,680
Prepaid expenses and other current assets	24,118	25,722
Total current assets	347,999	482,805
Property and equipment, net	68,094	57,442
Tradenames, net	115,853	118,965
Patent and patent licenses, net	13,928	18,841
Customer relationships, net	208,155	197,319
Goodwill	1,122,810	807,661	635,675
Other purchased intangibles, net	173,755	17,516
Other assets	6,445	4,607
Total assets	2,062,328	1,783,719
Accounts payable and accrued expenses	178,071	114,384
Income taxes payable	16,753	5,589
Deferred revenue, current	80,384	76,104
Total current liabilities	454,089	196,654
Long-term debt	601,746	592,037
Deferred income taxes, non-current	40,357	43,989
Other long-term liabilities	3,475	18,228
Total liabilities	1,147,792	893,511
Additional paid-in capital	308,329	292,064
Retained earnings	660,382	626,789
Accumulated other comprehensive loss	(54,649)	(29,124)	(7,127)
Total stockholders’ equity	914,536	890,208	$ 820,235	$ 706,418
Total liabilities and stockholders’ equity	2,062,328	1,783,719
Unrestricted Subsidiaries [Member]
Cash and cash equivalents	17,931	16,482
Accounts receivable	158,730	79,283
Prepaid expenses and other current assets	13,494	5,437
Deferred income taxes	0	3,382
Total current assets	190,155	104,584
Property and equipment, net	38,752	25,353
Tradenames, net	69,093	73,034
Patent and patent licenses, net	13,303	18,071
Customer relationships, net	95,855	68,317
Goodwill	563,658	304,943
Other purchased intangibles, net	163,023	7,810
Deferred income taxes	482	2,373
Other assets	5,541	0
Total assets	1,139,862	604,485
Accounts payable and accrued expenses	163,130	88,580
Income taxes payable	4,353	0
Deferred revenue, current	13,773	6,554
Total current liabilities	181,256	95,134
Long-term debt	602,662	155,000
Deferred income taxes, non-current	11,816	11,270
Other long-term liabilities	1,454	13,546
Total liabilities	797,188	274,950
Additional paid-in capital	318,160	319,728
Retained earnings	27,004	11,552
Accumulated other comprehensive loss	(2,490)	(1,745)
Total stockholders’ equity	342,674	329,535
Total liabilities and stockholders’ equity	$ 1,139,862	$ 604,485