CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net sales	$ 251,754	$ 234,751	$ 469,846	$ 435,190
Cost of goods sold - materials	72,899	68,514	136,998	126,622
Personnel costs	83,435	81,014	167,054	159,903
Other operating expenses	51,256	44,603	93,389	81,993
Relocation expenses		42		417
Depreciation and amortization	8,438	7,696	16,723	14,988
Income from operations	35,726	32,882	55,682	51,267
Interest expense	7,684	7,791	15,461	16,170
Income before taxes	28,042	25,091	40,221	35,097
Provision for income taxes	10,656	9,660	15,280	13,453
Net income	17,386	15,431	24,941	21,644
Comprehensive income	$ 17,386	$ 15,431	$ 24,941	$ 21,644
Basic Per Common Share Data
Net income (in dollars per share)	$ 0.51	$ 0.46	$ 0.73	$ 0.65
Shares used to compute basic per common share amounts (in shares)	34,268,941	33,499,268	34,110,820	33,429,502
Diluted Per Common Share Data
Net income (in dollars per share)	$ 0.50	$ 0.45	$ 0.72	$ 0.63
Shares used to compute diluted per common share amounts (in shares)	34,720,489	34,365,395	34,637,769	34,284,513