Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Business Segment Information [Abstract]
Number of business segments			2
Total assets [Abstract]
Total Assets	$ 913,520		$ 913,520		$ 828,640
Long-lived assets by segment	456,753		456,753		440,266
Segment information [Abstract]
Net Sales from external Customers	347,944	383,085	1,061,798	1,051,135
Inter Segment Sales	0	0	0	0
Gross Profit	171,235	200,594	544,104	551,922
Operating income	63,447	96,607	197,061	254,717
Income before income taxes	59,037	93,113	184,463	245,317
Depreciation and amortization (including stock-based compensation amortization)	5,480	12,166	30,538	36,475
Capital expenditures	17,730	6,743	38,394	18,841
North America [Member]
Total assets [Abstract]
Total Assets	766,923		766,923		688,001
Long-lived assets by segment	388,917		388,917		378,267
Segment information [Abstract]
Net Sales from external Customers	240,867	279,327	736,447	755,442
Inter Segment Sales	381	2,465	756	2,778
Gross Profit	105,024	139,744	348,468	375,760
Operating income	34,832	69,390	120,299	179,789
Income before income taxes	30,278	65,827	107,807	170,882
Depreciation and amortization (including stock-based compensation amortization)	2,647	9,255	22,312	28,516
Capital expenditures	14,625	4,434	27,701	11,392
North America [Member] | Mattresses [Member]
Segment information [Abstract]
Net Sales from external Customers	164,293	192,683	508,583	527,398
North America [Member] | Pillows [Member]
Segment information [Abstract]
Net Sales from external Customers	20,182	19,182	56,672	53,502
North America [Member] | Other Products [Member]
Segment information [Abstract]
Net Sales from external Customers	56,392	67,462	171,192	174,542
International [Member]
Total assets [Abstract]
Total Assets	480,647		480,647		422,246
Long-lived assets by segment	67,836		67,836		61,999
Segment information [Abstract]
Net Sales from external Customers	107,077	103,758	325,351	295,693
Inter Segment Sales	910	864	1,382	2,092
Gross Profit	66,211	60,850	195,636	176,162
Operating income	28,615	27,217	76,762	74,928
Income before income taxes	28,759	27,286	76,656	74,435
Depreciation and amortization (including stock-based compensation amortization)	2,833	2,911	8,226	7,959
Capital expenditures	3,105	2,309	10,693	7,449
International [Member] | Mattresses [Member]
Segment information [Abstract]
Net Sales from external Customers	64,046	63,122	200,228	178,361
International [Member] | Pillows [Member]
Segment information [Abstract]
Net Sales from external Customers	21,958	18,937	61,063	54,215
International [Member] | Other Products [Member]
Segment information [Abstract]
Net Sales from external Customers	21,073	21,699	64,060	63,117
Intercompany Elimination [Member]
Total assets [Abstract]
Total Assets	(334,050)		(334,050)		(281,607)
Segment information [Abstract]
Inter Segment Sales	$ (1,291)	$ (3,329)	$ (2,138)	$ (4,870)