Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Cash Flow Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 251,000,000	$ 114,762,000
Cash flows - operating activities
Net income	8,666,000	12,087,000
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	2,337,000	2,734,000
Deferred Income Tax Expense (Benefit)	110,000	336,000
Stock-based compensation expense	2,614,000	1,343,000
Accretion expense related to earnout payments	0	(160,000)
Marketable Securities, Gain (Loss)	(111,000)	0
Gain (Loss) on Disposition of Assets	1,000	0
Increase (Decrease) in Accounts Receivable	(24,656,000)	(20,167,000)
Changes in assets and liabilities:
Accounts payable	1,897,000	99,000
Accrued expenses	(147,265,000)	(146,222,000)
Restructuring Reserve, Accrual Adjustment	(138,000)	(681,000)
Deferred revenue	837,000	(1,586,000)
Income taxes payable, net	4,082,000	2,496,000
Retirement and pension plan assets and liabilities	2,033,000	1,550,000
Prepaid expenses	(6,566,000)	(6,499,000)
Other assets and liabilities, net	(9,441,000)	(923,000)
Net Cash Provided by (Used in) Operating Activities	165,600,000	(155,273,000)
Cash flows - investing activities
Payments to Acquire Property, Plant, and Equipment	1,753,000	898,000
Purchases of available-for-sale investments	(2,125,000)	(1,678,000)
Proceeds from sales of available-for-sale investments	61,395,000	113,000
Net Cash Provided by (Used in) Investing Activities	57,517,000	(2,463,000)
Net Cash Provided by (Used in) Financing Activities	(92,660,000)	(7,894,000)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	(5,296,000)	130,000
Cash flows - financing activities
Proceeds from Lines of Credit	100,000,000	0
Cash dividends paid	(3,002,000)	(2,935,000)
Payment of employee tax withholdings on equity transactions	(1,550,000)	(4,552,000)
Payment for Contingent Consideration Liability, Financing Activities	(2,788,000)	(407,000)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(20,719,000)	(165,500,000)
Cash, cash equivalents and restricted cash at end of period	$ 251,000,000	$ 114,414,000