Current and Noncurrent Accrued and Other Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Summary of current and noncurrent accrued and other liabilities
Customer deposits	$ 12,240		$ 4,505
Deferred revenue on extended warranty contracts	6,836		6,461
Accrued warranty costs	6,076	6,078	5,370	4,993	4,598	3,996
Accrued payroll and benefits	4,349		7,267
Accrued death benefits	4,200		4,017
Accrued income taxes	2,618		709
Accrued contractual manufacturing obligations	2,478		1,613
Fair value of derivatives and other	2,282		2,283
Accrued group health and workers' compensation insurance claims	2,225		2,535
Deferred gain on property insurance recovery	1,613
Accrued commissions	1,546		1,016
Accrued executive benefits	1,417		1,262
Other	7,413		6,878
Total current and noncurrent accrued liabilities	55,293		43,916
Less noncurrent portion	16,531		15,239
Current portion of accrued and other liabilities	$ 38,762		$ 28,677