SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 M	Mar. 31, 2011	Dec. 31, 2011
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Inventories	$ 120,485,000		$ 112,305,000
Accrued expenses	19,325,000		17,547,000
Material costs	66,697,000	59,111,000
Personnel costs	81,153,000	78,267,000
Other operating expenses	40,219,000	36,100,000
Income from operations	21,737,000	19,293,000
Income before taxes	13,960,000	10,914,000
Provision for income taxes	5,324,000	4,162,000
Net Income	8,636,000	6,752,000
Basic earnings per share	$ 0.25	$ 0.20
Diluted earnings per share	$ 0.25	$ 0.20
Net cash used in operating activities	1,292,000	(12,311,000)
Net cash (used in) provided by financing activities	(1,102,000)	6,044,000
Cash and Cash Equivalents
Maximum maturities of highly liquid investments to be considered as cash equivalents (in months)	3
Restricted Cash
Restricted cash to eliminate letters of credit obligations	3,100,000
Misclassification within consolidated statements of cash flows
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Net cash used in operating activities		(12,311,000)
Net cash (used in) provided by financing activities		6,044,000
Misclassification within consolidated statements of cash flows | As Previously Reported
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Net cash used in operating activities		(11,495,000)
Net cash (used in) provided by financing activities		5,228,000
Misclassification within consolidated statements of cash flows | Adjustment
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Net cash used in operating activities		(816,000)
Net cash (used in) provided by financing activities		816,000
Overstatement of Value of Work in Progress Inventory
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Inventories			112,305,000
Accrued expenses			17,547,000
Material costs	66,697,000	59,111,000
Personnel costs	81,153,000	78,267,000
Other operating expenses	40,219,000	36,100,000
Income from operations	21,737,000	19,293,000
Income before taxes	13,960,000	10,914,000
Provision for income taxes	5,324,000	4,162,000
Net Income	8,636,000	6,752,000
Basic earnings per share	$ 0.25	$ 0.20
Diluted earnings per share	$ 0.25	$ 0.20
Overstatement of Value of Work in Progress Inventory | As Previously Reported
Revision of Previously Reported Statement of Cash Flow Information and Consolidated Financial Information
Inventories			114,086,000
Accrued expenses			18,247,000
Material costs	64,098,000	58,108,000
Personnel costs	83,619,000	78,889,000
Other operating expenses	42,133,000	37,390,000
Income from operations	19,956,000	18,384,000
Income before taxes	12,179,000	10,005,000
Provision for income taxes	4,624,000	3,792,000
Net Income	$ 7,555,000	$ 6,213,000
Basic earnings per share	$ 0.22	$ 0.19
Diluted earnings per share	$ 0.22	$ 0.18