Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net earnings	$ 118,985	$ 113,430	$ 385,405
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	57,955	60,708	61,446
Amortization of debt issuance costs	1,847	3,028	2,353
Provision for losses on accounts receivable	821	4,024	10,138
Goodwill, Impairment Loss	7,585	0	0
Loss on extinguishment of debt	0	5,748	3,429
(Gain) loss on derivatives, net	(1,251)	6,326	18,816
Gain (loss) on sale of property, plant and equipment	727	72	(47)
Stock-based compensation expense	13,908	12,908	32,125
Deferred income taxes	9,448	7,951	3,520
Impairment of Intangible Assets, Finite-lived	0	7,134	0
Changes in assets and liabilities:
Accounts receivable, net	26,148	7,608	(41,254)
Inventories	(2,133)	867	(1,515)
Prepaid expenses and other	2,299	(221)	4,297
Other assets	448	(532)	(1,259)
Accounts payable	(54,769)	4,776	(8,817)
Progress billings	380	13,026	(12,469)
Accrued expenses	8,225	7,194	18,262
Other non-current liabilities	8,478	(2,536)	(7,522)
Total adjustments	27,054	86,811	77,921
Net cash provided by (used in) operating activities	146,039	200,241	463,326
Cash flows from investing activities:
Additions to property, plant and equipment	(21,194)	(21,720)	(26,678)
Payments to Acquire Businesses, Net of Cash Acquired	(18,653)	0	0
Payments to Acquire Intangible Assets	0	0	(7,582)
Proceeds from sale of property, plant and equipment	261	200	99
Proceeds from sale of available-for-sale securities	0	1,494	465
Net cash used in investing activities	(39,586)	(20,026)	(33,696)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from Issuance of Debt	0	610,000	0
Repayments of long-term debt	(15,000)	(713,667)	(304,845)
Debt issuance costs	0	(11,695)	0
Repurchases of common stock	(111,962)	(215,071)	(58,225)
Proceeds from issuance of common stock	11,802	6,814	49,461
Net cash provided (used in) by financing activities	(115,160)	(323,619)	(313,609)
Effect of exchange rate changes on cash and cash equivalents	1,447	(560)	68
Net increase (decrease) in cash and cash equivalents	(7,260)	(143,964)	116,089
Cash and cash equivalents at beginning of period	101,971	245,935	129,846
Cash and cash equivalents at end of period	94,711	101,971	245,935
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	27,673	31,349	72,394
Cash paid during the period for income taxes	80,015	81,539	237,674
Non-cash financing activities:
Stock issued under stock-based compensation plans	$ 0	$ 3,385	$ 7,634