Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net earnings	$ 21,669	$ 26,421
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	13,287	14,710
Amortization of debt issuance costs	905	518
Provision for losses on accounts receivable	751	543
Loss (gain) on derivatives, net	170	(178)
Gain (loss) on sale of property, plant and equipment	920	(79)
Stock-based compensation expense	2,986	2,287
Deferred income taxes	1,179	1,004
Changes in assets and liabilities:
Accounts receivable, net	9,359	30,767
Inventories	4,178	7,184
Prepaid expenses and other	6,307	10,939
Other assets	(582)	873
Accounts payable	(4,755)	(52,505)
Progress billings	(3,276)	4,156
Accrued expenses	(28,240)	(31,629)
Other non-current liabilities	(1,408)	(637)
Total adjustments	1,781	(12,047)
Net cash provided by (used in) operating activities	23,450	14,374
Cash flows from investing activities:
Additions to property, plant and equipment	(3,342)	(9,265)
Proceeds from sale of property, plant and equipment	5,099	79
Net cash provided by (used in) investing activities	1,757	(9,186)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Repayments of long-term debt	(3,750)	(3,750)
Dividends paid on common shares and restricted stock	(12,011)	0
Repurchases of common stock	(21,168)	(1,366)
Proceeds from issuance of common stock	14,836	5,685
Net cash provided (used in) by financing activities	(22,093)	569
Effect of exchange rate changes on cash and cash equivalents	(621)	(529)
Net increase (decrease) in cash and cash equivalents	2,493	5,228
Cash and cash equivalents at beginning of period	94,711	101,971
Cash and cash equivalents at end of period	97,204	107,199
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	11,003	11,192
Cash paid during the period for income taxes	$ 2,640	$ 7,630