Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income	$ 31,341,000	$ 32,328,000
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	21,951,000	19,152,000
Noncash lease expense	7,473,000	8,023,000
Stock-based compensation expense	3,918,000	3,443,000
Deferred income taxes	(2,136,000)	1,462,000
Contract loss reserve	(527,000)	0
Bad debt expense	(14,000)	(999,000)
Change in assets and liabilities—net of effects from acquired businesses:
Receivables-net	3,220,000	(26,823,000)
Prepaid expenses	(7,822,000)	(3,960,000)
Taxes receivable—current	12,259,000	7,629,000
Other current assets	1,759,000	1,295,000
Employee supplemental savings plan asset	3,056,000	(358,000)
Other assets	(2,221,000)	(2,051,000)
Accounts payable	(10,420,000)	(19,862,000)
Accrued salaries and related expenses	(6,518,000)	(3,015,000)
Contract liabilities	(6,351,000)	(6,386,000)
Accrued expenses and other current liabilities	1,712,000	(4,963,000)
Operating lease obligations	(9,692,000)	(8,941,000)
Accrued retirement	(6,352,000)	(3,750,000)
Other	(160,000)	(404,000)
Net cash flow from (used in) operating activities	34,476,000	(8,180,000)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Purchases of property and equipment	(16,204,000)	(17,854,000)
Proceeds from corporate owned life insurance	5,000,000	0
Net cash used in investing activities	(11,204,000)	(17,854,000)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Dividends paid	(16,741,000)	(15,388,000)
Proceeds from exercise of stock options	4,010,000	3,142,000
Payment consideration to tax authority on employee's behalf	(3,629,000)	(2,489,000)
Borrowings under credit facility	2,000,000	131,000,000
Repayments under credit facility	(2,000,000)	(124,500,000)
Net cash from used in financing activities	(16,360,000)	(8,235,000)
NET CHANGE IN CASH AND CASH EQUIVALENTS	6,912,000	(34,269,000)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	53,374,000	41,193,000
CASH AND CASH EQUIVALENTS, END OF PERIOD	60,286,000	6,924,000
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for interest	2,159,000	327,000
Cash paid for income taxes, net of refunds	295,000	10,000
Noncash investing and financing activities:
Operating lease obligations arising from obtaining right of use assets	14,978,000	5,401,000
Finance lease obligations arising from obtaining right of use assets	0	62,000
Noncash investing activities	$ (643,000)	$ 479,000