Quarterly Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended		3 Months Ended																12 Months Ended
	Jul. 16, 2014	Jul. 02, 2013	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales			$ 84,728		$ 102,917		$ 92,310		$ 76,367		$ 73,376		$ 89,690		$ 91,241		$ 66,833		$ 356,322		$ 321,140		$ 303,114
Gross profit			25,191		33,350		27,876		21,846		20,188		26,616		27,676		15,312		108,263		89,792		70,499
Net income			$ 10,533		$ 12,440		$ 11,363		$ 9,822		$ 7,766		$ 10,522		$ 12,119		$ 7,140		$ 44,158		$ 37,547		$ 27,449
Earnings per share:
Basic (usd per share)			$ 0.19	[1]	$ 0.23	[1]	$ 0.21	[1]	$ 0.18	[1]	$ 0.14	[1]	$ 0.19	[1]	$ 0.22	[1]	$ 0.13	[1]	$ 0.81	[1]	$ 0.68	[1]	$ 0.50	[1]
Diluted (usd per share)			$ 0.19	[1]	$ 0.22	[1]	$ 0.20	[1]	$ 0.17	[1]	$ 0.14	[1]	$ 0.19	[1]	$ 0.22	[1]	$ 0.13	[1]	$ 0.80	[1]	$ 0.68	[1]	$ 0.49	[1]
Stock split, conversion ratio	1.5	1.5

[1] Reflects three-for-two stock split effective July 16, 2014