CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Activities
Net loss	$ (19,826)	$ (8,687)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	15,970	14,961
Gain on sales of property and equipment	(1,087)	(1,917)
Stock-based compensation	5,386	4,196
Changes in assets and liabilities, net of the effects of a acquisition:
Receivables	63,694	41,950
Costs and estimated earnings in excess of billings, net	(29,395)	(15,734)
Inventories	(6,506)	(16,807)
Equity in construction joint ventures	(64,874)	9,078
Other assets, net	(6,505)	(2,202)
Accounts payable	(31,985)	(29,178)
Accrued expenses and other current liabilities, net	20,475	(18,533)
Net cash used in operating activities	(54,653)	(22,873)
Investing Activities
Purchases of marketable securities	(14,975)	(24,987)
Maturities of marketable securities	20,000	15,000
Proceeds from sale of marketable securities	5,000	20,000
Additions to property and equipment	(9,956)	(9,225)
Proceeds from sales of property and equipment	3,417	2,883
Other investing activities, net	(57)	(294)
Net cash provided by (used in) investing activities	3,429	3,377
Financing Activities
Long-term debt principal payments	0	(2,500)
Cash dividends paid	(5,045)	(5,021)
Purchase of common stock	(4,907)	(3,837)
Other financing activities, net	(41)	90
Net cash used in financing activities	(9,993)	(11,268)
Decrease in cash and cash equivalents	(61,217)	(30,764)
Cash and cash equivalents at beginning of period	321,990	256,990
Cash and cash equivalents at end of period	260,773	226,226
Cash paid during the period for:
Interest	276	610
Income taxes	1,272	305
Non-cash investing and financing activities:
Restricted stock units issued, net of forfeitures	13,402	10,940
Accrued cash dividends	5,045	5,021
Debt payments out of escrow from sale of assets	0	659
Debt extinguishment from joint venture interest transfer	0	9,115
Debt payment from refinancing	$ 0	$ 1,150