Segments Segments (External Customer Sales By Product) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue from External Customer [Line Items]
Total net sales	$ 510,162	$ 416,471	$ 357,287	$ 292,826	$ 311,848	$ 358,314	$ 351,620	$ 289,716	$ 1,576,746	$ 1,311,498	$ 1,210,156
Structural components [Member]
Revenue from External Customer [Line Items]
Total net sales									249,371	205,036	190,626
Millwork & other interior products [Member]
Revenue from External Customer [Line Items]
Total net sales									459,446	428,084	419,436
Lumber & lumber sheet goods [Member]
Revenue from External Customer [Line Items]
Total net sales									442,675	328,063	278,704
Other building products & services [Member]
Revenue from External Customer [Line Items]
Total net sales									$ 425,254	$ 350,315	$ 321,390