Consolidated Statement 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	$ 20,574	$ 22,278
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,158	7,922
Deferred income taxes	6,841	(681)
Provision for uncollectible accounts receivable	3,304	2,967
Amortization of discount on convertible notes	2,261	2,114
Stock option expense	1,309	1,491
Amortization of debt issuance costs	337	780
Noncash portion of long-term incentive compensation	373	612
Changes in operating assets and liabilities, excluding amounts acquired in business combinations:
Increase in accounts receivable	(27,700)	(36,706)
Decrease in inventories	27	499
Increase in prepaid expenses	(1,112)	(1,092)
Decrease in accounts payable and other current liabilities	(32,561)	(698)
Increase in income taxes	5,322	10,139
Increase in other assets	(1,069)	(3,071)
Increase in other liabilities	3,080	3,282
Excess tax benefit on share-based compensation	(1,399)	(1,891)
Other sources	409	196
Net cash provided/(used) by operating activities	(11,846)	8,141
Cash Flows from Investing Activities
Capital expenditures	(8,131)	(5,406)
Business combinations, net of cash acquired	(250)
Other sources	29	78
Net cash used by investing activities	(8,352)	(5,328)
Cash Flows from Financing Activities
Purchases of treasury stock	(32,982)
Dividends paid	(3,303)	(3,367)
Capital stock surrendered to pay taxes on stock-based compensation	(2,916)	(3,389)
Proceeds from exercise of stock options	13,193	10,168
Excess tax benefit on share-based compensation	1,399	1,891
Increase/(decrease) in cash overdrafts payable	369	(3,165)
Debt issuance costs		(1,107)
Other uses	(501)	(419)
Net cash provided/(used) by financing activities	(24,741)	612
Increase/(Decrease) in Cash and Cash Equivalents	(44,939)	3,425
Cash and cash equivalents at beginning of year	84,418	69,531
Cash and cash equivalents at end of period	$ 39,479	$ 72,956