Supplemental Guarantor Information Consolidating Condensed Statement of Cash Flows (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided (Used) by Operating Activities	$ 62,291,000	$ 99,078,000	$ 122,207,000
Investing Activities
Purchases of property and equipment	(20,091,000)	(22,160,000)	(17,353,000)
Proceeds from sale of property and equipment	159,000	64,000	36,000
Business acquisitions, net of cash acquired	(9,000,000)	(42,430,000)	(13,725,000)
Other long-term assets	(265,000)	(724,000)	801,000
Other	(245,000)	(13,000)	(376,000)
Net Cash Used for Investing Activities	(29,442,000)	(65,263,000)	(30,617,000)
Financing Activities
Proceeds from revolving lines of credit and long-term borrowings	339,314,000	450,595,000	708,742,000
Payments on revolving lines of credit and long-term borrowings	(367,500,000)	(454,567,000)	(751,660,000)
Proceeds from exercise of stock options	0	4,139,000	2,912,000
Payments of Financing Costs	(1,000)	(24,113,000)	(30,329,000)
Payment of dividends	(1,581,000)	(1,588,000)	(1,612,000)
Purchase of treasury stock	0	(21,548,000)	(5,687,000)
Net Cash Provided (Used) by Financing Activities	(29,768,000)	(47,082,000)	(77,634,000)
Effect of exchange rate changes on cash	786,000	(271,000)	(2,995,000)
Increase (decrease) in cash and cash equivalents	3,867,000	(13,538,000)	10,961,000
Cash and cash equivalents at beginning of year	34,924,000	48,462,000	37,501,000
Cash and cash equivalents at end of year	38,791,000	34,924,000	48,462,000
The Company (Parent) [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided (Used) by Operating Activities	(46,194,000)	38,724,000	101,658,000
Investing Activities
Purchases of property and equipment	(2,266,000)	(6,887,000)	(7,281,000)
Proceeds from sale of property and equipment	12,000	0	0
Business acquisitions, net of cash acquired	0	0	0
Other long-term assets	(381,000)	(731,000)	291,000
Other	82,999,000	(219,000)	153,000
Net Cash Used for Investing Activities	80,364,000	(7,837,000)	(6,837,000)
Financing Activities
Proceeds from revolving lines of credit and long-term borrowings	337,044,000	450,595,000	689,022,000
Payments on revolving lines of credit and long-term borrowings	(367,500,000)	(438,766,000)	(751,660,000)
Proceeds from exercise of stock options	0	4,139,000	2,912,000
Payments of Financing Costs	(1,000)	(24,113,000)	(30,329,000)
Payment of dividends	(1,581,000)	(1,588,000)	(1,612,000)
Purchase of treasury stock	0	(21,548,000)	(5,687,000)
Net Cash Provided (Used) by Financing Activities	(32,038,000)	(31,281,000)	(97,354,000)
Effect of exchange rate changes on cash	0	0	0
Increase (decrease) in cash and cash equivalents	2,132,000	(394,000)	(2,533,000)
Cash and cash equivalents at beginning of year	3,642,000	4,036,000	6,569,000
Cash and cash equivalents at end of year	5,774,000	3,642,000	4,036,000
Combined Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided (Used) by Operating Activities	26,243,000	49,396,000	15,427,000
Investing Activities
Purchases of property and equipment	(9,643,000)	(5,316,000)	(1,567,000)
Proceeds from sale of property and equipment	23,000	16,000	0
Business acquisitions, net of cash acquired	(9,000,000)	(42,430,000)	(13,725,000)
Other long-term assets	0	0	(11,000)
Other	(10,849,000)	73,000	(174,000)
Net Cash Used for Investing Activities	(29,469,000)	(47,657,000)	(15,477,000)
Financing Activities
Proceeds from revolving lines of credit and long-term borrowings	2,140,000	0	0
Payments on revolving lines of credit and long-term borrowings	0	(2,111,000)	0
Proceeds from exercise of stock options	0	0	0
Payments of Financing Costs	0	0	0
Payment of dividends	0	0	0
Purchase of treasury stock	0	0	0
Net Cash Provided (Used) by Financing Activities	2,140,000	(2,111,000)	0
Effect of exchange rate changes on cash	0	0	0
Increase (decrease) in cash and cash equivalents	(1,086,000)	(372,000)	(50,000)
Cash and cash equivalents at beginning of year	2,104,000	2,476,000	2,526,000
Cash and cash equivalents at end of year	1,018,000	2,104,000	2,476,000
Combined Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided (Used) by Operating Activities	14,326,000	65,516,000	44,442,000
Investing Activities
Purchases of property and equipment	(8,182,000)	(9,957,000)	(8,505,000)
Proceeds from sale of property and equipment	124,000	48,000	36,000
Business acquisitions, net of cash acquired	0	0	0
Other long-term assets	116,000	7,000	521,000
Other	46,000	133,000	(355,000)
Net Cash Used for Investing Activities	(7,896,000)	(9,769,000)	(8,303,000)
Financing Activities
Proceeds from revolving lines of credit and long-term borrowings	130,000	0	19,720,000
Payments on revolving lines of credit and long-term borrowings	0	(13,690,000)	0
Proceeds from exercise of stock options	0	0	0
Payments of Financing Costs	0	0	0
Payment of dividends	(4,525,000)	(54,558,000)	(39,320,000)
Purchase of treasury stock	0	0	0
Net Cash Provided (Used) by Financing Activities	(4,395,000)	(68,248,000)	(19,600,000)
Effect of exchange rate changes on cash	786,000	(271,000)	(2,995,000)
Increase (decrease) in cash and cash equivalents	2,821,000	(12,772,000)	13,544,000
Cash and cash equivalents at beginning of year	29,178,000	41,950,000	28,406,000
Cash and cash equivalents at end of year	31,999,000	29,178,000	41,950,000
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided (Used) by Operating Activities	67,916,000	(54,558,000)	(39,320,000)
Investing Activities
Purchases of property and equipment	0	0	0
Proceeds from sale of property and equipment	0	0	0
Business acquisitions, net of cash acquired	0	0	0
Other long-term assets	0	0	0
Other	(72,441,000)	0	0
Net Cash Used for Investing Activities	(72,441,000)	0	0
Financing Activities
Proceeds from revolving lines of credit and long-term borrowings	0	0	0
Payments on revolving lines of credit and long-term borrowings	0	0	0
Proceeds from exercise of stock options	0	0	0
Payments of Financing Costs	0	0	0
Payment of dividends	4,525,000	54,558,000	39,320,000
Purchase of treasury stock	0	0	0
Net Cash Provided (Used) by Financing Activities	4,525,000	54,558,000	39,320,000
Effect of exchange rate changes on cash	0	0	0
Increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	$ 0	$ 0	$ 0