Quarterly Financial Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 26, 2014	Sep. 27, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 417,590	$ 419,876	$ 406,613	$ 347,236	$ 299,585	$ 277,941	$ 256,226	$ 246,169	$ 1,095,533	$ 1,591,315	$ 1,079,921	$ 1,095,533
Gross Profit	126,085	132,640	127,331	108,199	97,011	77,106	69,781	68,992
Operating income	47,374	62,984	60,308	42,722	61,985	(37,285)	44,240	43,096		213,388	112,036	154,933
Net income (loss) applicable to common shares	$ 11,594	$ 14,879	$ 7,925	$ 2,580	$ 64,005	$ (36,891)	$ 13,511	$ (1,681)		$ 36,978	$ 38,944	$ 30,622
Per basic common share:
Net income applicable to common shares (in dollars per share)	$ 0.11	$ 0.14	$ 0.08	$ 0.03	$ 0.64	$ (0.39)	$ 0.14	$ (0.02)		$ 0.35	$ 0.39	$ 0.32
Per diluted common share:
Net income applicable to common shares (in dollars per share)	$ 0.11	$ 0.14	$ 0.08	$ 0.03	$ 0.59	$ (0.39)	$ 0.14	$ (0.02)		$ 0.35	$ 0.39	$ 0.32
Stock dividend paid													5.00%	5.00%