CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME
Net sales	$ 235,605	$ 229,350
Material costs	67,345	67,739
Personnel costs	96,431	89,953
Other operating expenses	45,600	39,657
Depreciation and amortization	10,199	9,285
Income from operations	16,030	22,716
Interest expense	6,098	7,777
Income before taxes	9,932	14,939
Provision for income taxes	3,935	5,449
Net income	5,997	9,490
Comprehensive income	$ 5,997	$ 9,490
Basic Per Common Share Data
Net income (in dollars per share)	$ 0.17	$ 0.27
Shares used to compute basic per common share amounts (in shares)	35,076,828	34,598,494
Diluted Per Common Share Data
Net income (in dollars per share)	$ 0.17	$ 0.27
Shares used to compute diluted per common share amounts (in shares)	35,415,018	35,066,032