CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 62,882	$ 62,567	$ 35,711
Adjustments to reconcile net income to net cash provided by operating activities-
Depreciation	13,616	14,776	14,084
Amortization	27,626	29,281	33,553
Amortization of original issue discount	4,866	6,246	5,781
Asset impairment	194	1,685
(Gain) loss on short-term investments and other	(83)	177	1,123
Loss on repurchase of convertible notes	8,651
Gain on disposition of business operations	(6,611)	(3,733)	(222)
Deferred income taxes	(2,811)	(16,106)	41
Excess tax benefit of stock-based compensation awards	(4,729)	(2,185)	(2,060)
Stock-based compensation	22,715	21,130	16,655
Changes in operating assets and liabilities, net of acquired amounts:
Trade accounts receivable, net	(23,243)	1,831	(14,326)
Other current and non-current assets	255	(5,387)	(3,230)
Income taxes payable/receivable	(14,167)	8,953	(2,260)
Trade accounts payable and accrued liabilities	(5,738)	13,916	4,359
Deferred revenue	957	3,808	(5,558)
Net cash provided by operating activities	84,186	136,959	83,651
Cash flows from investing activities:
Purchases of property and equipment	(14,263)	(18,845)	(25,985)
Purchases of short-term investments	(196,967)	(181,553)	(190,427)
Proceeds from sale/maturity of short-term investments	157,825	192,994	197,466
Acquisition of and investments in business, net of cash acquired		(1,300)
Acquisition of and investments in client contracts	(7,587)	(8,018)	(5,600)
Proceeds from the disposition of business operations	8,850		1,130
Net cash used in investing activities	(52,142)	(16,722)	(23,416)
Cash flows from financing activities:
Proceeds from issuance of common stock	1,547	1,547	1,394
Payment of cash dividends	(24,110)	(22,238)	(20,530)
Repurchase of common stock	(25,196)	(65,027)	(25,138)
Payments on acquired asset financing		(829)	(1,097)
Proceeds from long-term debt	230,000	150,000
Payments on long-term debt	(7,500)	(127,500)	(15,000)
Repurchase of convertible notes	(215,676)
Payments of deferred financing costs	(6,744)	(2,742)
Excess tax benefit of stock-based compensation awards	4,729	2,185	2,060
Net cash used in financing activities	(42,950)	(64,604)	(58,311)
Effect of exchange rate fluctuations on cash	4,626	(4,714)	(2,898)
Net increase (decrease) in cash and cash equivalents	(6,280)	50,919	(974)
Cash and cash equivalents, beginning of period	132,631	81,712	82,686
Cash and cash equivalents, end of period	126,351	132,631	81,712
Cash paid during the period for-
Interest	12,191	8,380	8,265
Income taxes	$ 53,020	$ 41,860	$ 25,153