Business Acquisitions and Investments, Pro Forma Information (Unaudited) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition, Pro Forma Information [Abstract]
Net revenues	$ 218,708	$ 264,162	$ 270,126	$ 230,708	$ 192,355	$ 275,975	$ 268,875	$ 211,711	$ 983,704	$ 948,916	$ 874,625
Net earnings	8,936	17,297	16,043	9,174	5,915	16,840	13,404	5,194	51,450	41,353	62,401
Pro Forma Net sales									984,019	970,279
Pro Forma Net earnings									$ 51,598	$ 43,282