Quarterly Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information Disclosure [Abstract]

Summary of selected quarterly financial data

The following tables summarize selected quarterly financial data for the years ended December 31, 2014 and 2013:

	2014
(Thousands except per share amounts)	First Quarter			Second Quarter			Third Quarter			Fourth Quarter			Total
Net sales	$	258,929		$	287,965		$	291,570		$	288,426		$	1,126,890
Gross margin	45,462			49,801			54,843			55,797			205,903
Percent of net sales	17.6		%	17.3		%	18.8		%	19.3		%	18.3		%
Net income	$	7,331		$	9,974		$	12,440		$	11,976		$	41,721
Net income per share of common stock:
Basic	$	0.36		$	0.48		$	0.61		$	0.59		$	2.04
Diluted	0.35			0.47			0.60			0.58			2.00
Cash dividends per share of common stock	0.08			0.085			0.085			0.085			0.335
Stock price range:
High	$	35.19		$	37.96		$	39.38		$	40.60
Low	25.21			31.69			30.88			26.64
	2013
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter			Total
Net sales	$	299,169		$	306,141		$	275,434		$	286,138		$	1,166,882
Gross margin	48,339			45,992			44,483			49,164			187,978
Percent of net sales	16.2		%	15.0		%	16.2		%	17.2		%	16.1		%
Net income	$	6,785		$	4,155		$	4,992		$	3,775		$	19,707
Net income per share of common stock:
Basic	$	0.33		$	0.20		$	0.24		$	0.18		$	0.96
Diluted	0.33			0.20			0.24			0.18			0.94
Cash dividends per share of common stock	0.075			0.080			0.080			0.080			0.315
Stock price range:
High	$	29.81		$	31.49		$	33.69		$	32.73
Low	26.20			24.58			27.09			25.75