Acquisitions (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	May 01, 2013 Pipe and Foundation Group lb	Sep. 30, 2013 Pipe and Foundation Group
Business Acquisition [Line Items]
Annual production capacity of PVC pipe and fittings					150,000,000
Cash paid for purchase			$ 178,309	$ 0	$ 178,309
Net sales	1,004,165	821,175	2,807,859	2,770,000
Net income	170,290	86,964	439,453	290,278
Acquisition-related costs						$ 1,124