Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 9,376	$ 9,957
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	2,250	2,027
Stock-based compensation expense	1,000	878
Deferred income taxes	(676)	(538)
Loss on disposal of property and equipment	104	19
Changes in operating assets and liabilities:
(Increase) in trade accounts receivable, net	(8,797)	(10,683)
Decrease in prepaid expenses & other current assets	2,241	1,160
(Increase) in other assets	(34)	(1)
Increase in accounts payable	7,987	838
(Decrease) in accrued expenses	(7,227)	(2,901)
Increase in other current liabilities	415	15
Increase in other long-term liabilities	161	485
Net cash provided by operating activities	6,800	1,256
Cash flows from investing activities:
Purchases of property and equipment	(919)	(1,002)
Capitalized internal use software development costs	(325)	(380)
Net cash used in investing activities	(1,244)	(1,382)
Cash flows from financing activities:
Proceeds from employee common stock purchases	1,107	904
Tax deductions related to stock-based compensation	690	581
Net cash provided by financing activities	1,797	1,485
Net increase in cash	7,353	1,359
Cash, beginning of period	74,245	62,358
Cash, end of period	81,598	63,717
Non-cash investing activities:
Capital expenditures accrued but not yet paid	189	128
Cash payments:
Income taxes paid	6,532	3,001
Cash dividends on common stock previously restricted for payment of dividend	$ 22,982