CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME
Net sales	$ 985,550	$ 918,539	$ 817,379
Material costs	296,193	270,210	248,667
Personnel costs	335,328	321,529	282,417
Other operating expenses	188,868	177,910	165,158
Relocation expenses		1,185	16,444
Acquisition expenses	1,171	781	5,414
Depreciation and amortization	34,652	30,969	18,809
Income from operations	129,338	115,955	80,470
Interest expense, net	31,169	31,821	30,340
Extinguishment of debt			13,985
Loss from interest rate swap			1,610
Income before taxes	98,169	84,134	34,535
Provision for income taxes	34,477	29,657	13,639
Net income	63,692	54,477	20,896
Other comprehensive income (loss):
Unrealized gain on interest rate swaps, net of taxes of $1,912			2,868
Reclassification of net losses on auction rate securities from OCI to net income, net of taxes of $125			188
Unrealized loss on Retirement Plan, net of taxes of $440, $546 and $177 for 2012, 2011 and 2010, respectively	(734)	(906)	(279)
Total other comprehensive income (loss)	(734)	(906)	2,777
Comprehensive income	$ 62,958	$ 53,571	$ 23,673
Basic Per Common Share Data
Net income (in dollars per share)	$ 1.86	$ 1.62	$ 0.65
Shares used to compute basic per common share amounts (in shares)	34,282,591	33,544,813	32,238,401
Diluted Per Common Share Data
Net income (in dollars per share)	$ 1.83	$ 1.59	$ 0.64
Shares used to compute diluted per common share amounts (in shares)	34,832,830	34,220,256	32,888,305