CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME
Net sales	$ 233,535	$ 218,091
Material costs	67,739	66,697
Personnel costs	89,953	81,153
Other operating expenses	43,769	40,144
Acquisition expenses	73	75
Depreciation and amortization	9,285	8,285
Income from operations	22,716	21,737
Interest expense	7,777	7,777
Income before taxes	14,939	13,960
Provision for income taxes	5,449	5,324
Net income	9,490	8,636
Comprehensive income	$ 9,490	$ 8,636
Basic Per Common Share Data
Net income (in dollars per share)	$ 0.27	$ 0.25
Shares used to compute basic per common share amounts (in shares)	34,598,494	34,036,539
Diluted Per Common Share Data
Net income (in dollars per share)	$ 0.27	$ 0.25
Shares used to compute diluted per common share amounts (in shares)	35,066,032	34,639,660