Consolidated Statement Of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Flows from Operating Activities
Net income	$ 20,445,000	$ 18,101,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,354,000	7,258,000
Provision for deferred income taxes	(3,397,000)	814,000
Provision for uncollectible accounts receivable	2,245,000	2,111,000
Amortization of discount on convertible notes	1,975,000	1,846,000
Stock option expense	1,938,000	1,933,000
Noncash long-term incentive compensation		2,595,000
Changes in operating assets and liabilities, excluding amounts acquired in business combinations:
Decrease/(increase) in accounts receivable	(34,949,000)	17,923,000
Decrease/(increase) in inventories	200,000	(239,000)
Decrease in prepaid expenses	1,833,000	747,000
Decrease in accounts payable and other current liabilities	(3,894,000)	(12,137,000)
Increase in income taxes	15,532,000	9,739,000
Increase in other assets	(3,654,000)	(3,667,000)
Increase in other liabilities	5,241,000	3,227,000
Excess tax benefit on share-based compensation	(797,000)	(1,895,000)
Other sources	309,000	185,000
Net cash provided by operating activities	10,381,000	48,541,000
Cash Flows from Investing Activities
Capital expenditures	(12,018,000)	(6,173,000)
Business combinations, net of cash acquired	(415,000)
Other sources/(uses)	311,000	(109,000)
Net cash used by investing activities	(12,122,000)	(6,282,000)
Cash Flows from Financing Activities
Dividends paid	(3,072,000)	(2,977,000)
Purchases of treasury stock	(1,431,000)	(24,260,000)
Proceeds from issuance of capital stock	1,042,000	3,647,000
Excess tax benefit on share-based compensation	797,000	1,895,000
Increase/(decrease) in cash overdrafts payable	226,000	(8,310,000)
Debt issuance costs		(2,708,000)
Other sources	312,000	282,000
Net cash used by financing activities	(2,126,000)	(32,431,000)
Increase/(Decrease) in Cash and Cash Equivalents	(3,867,000)	9,828,000
Cash and cash equivalents at beginning of year	38,081,000	49,917,000
Cash and cash equivalents at end of period	$ 34,214,000	$ 59,745,000