Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 526,554	$ 575,615
Accounts receivable, net of allowances of $13,080 and $12,701, respectively	204,783	261,928
Prepaid expenses and other current assets	50,758	49,347
Total current assets	782,095	886,890
Long-term investments	98,020	100,079
Property and equipment, net	136,439	127,817
Operating Lease, Right-of-Use Asset	115,455	125,822
Trade names, net	134,438	138,029
Customer relationships, net	226,637	238,502
Goodwill	1,637,193	1,633,033
Other purchased intangibles, net	165,581	180,022
Other assets	14,462	15,676
Total assets	3,368,893	3,505,846
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable and accrued expenses	162,656	238,059
Income taxes payable, current	16,732	17,758
Deferred revenue, current	160,924	162,855
Operating Lease, Liability, Current	26,715	26,927
Current maturities of long-term debt	0	385,532
Other current liabilities	1,654	1,973
Total current liabilities	368,681	833,104
Long-term debt	1,455,446	1,062,929
Deferred revenue, noncurrent	12,225	12,744
Operating Lease, Liability, Noncurrent	93,687	104,070
Accrued Income Taxes, Noncurrent	11,675	11,675
Liability for uncertain tax positions	54,105	52,451
Deferred income taxes, non-current	105,257	107,453
Other long-term liabilities	26,736	10,228
Total liabilities	2,127,812	2,194,654
Commitments and contingencies	0	0
Preferred stock, $0.01 par value	0	0
Common stock, $0.01 par value. Authorized 95,000,000; total issued and outstanding 47,113,423 and 47,654,929 shares at March 31, 2020 and December 31, 2019, respectively.	471	476
Additional paid-in capital	462,430	465,652
Retained earnings	832,648	891,526
Accumulated other comprehensive loss	(54,468)	(46,462)
Stockholders' Equity Attributable to Parent	1,241,081	1,311,192
Total liabilities and stockholders’ equity	3,368,893	3,505,846
Deferred Tax Assets, Net, Noncurrent	$ 58,573	$ 59,976
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	95,000,000	95,000,000
Common stock, shares issued	47,113,423	47,654,929
Common stock, shares outstanding	47,113,423	47,654,929
Allowance for doubtful accounts	$ 13,080	$ 12,701
Series A Preferred Stock [Member]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Preferred stock, $0.01 par value	$ 0	$ 0
Preferred stock, shares authorized	6,000	6,000
Series B Preferred Stock [Member]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Preferred stock, $0.01 par value	$ 0	$ 0
Preferred stock, shares authorized	20,000	20,000