Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v2.4.0.8
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
6 Months Ended 12 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Dec. 31, 2013
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]            
Cash and cash equivalents $ 188,948,000 $ 363,113,000 $ 488,777,000 $ 273,340,000 $ 366,619,000 $ 394,701,000
Cash equivalents 17,200,000   247,800,000      
Cash and cash equivalents held in domestic bank accounts 39,700,000   236,700,000      
Cash and cash equivalents held in foreign bank accounts 149,200,000   252,100,000      
Number of days after accounts receivable are treated as delinquent 30 days   30 days      
Number of days related to outstanding accounts receivable for analysis of the allowance for doubtful accounts At least 90 days   At least 90 days      
Total allowances for doubtful accounts 6,246,000   5,215,000      
Current retainage balances 191,100,000   194,500,000      
Non-current retainage balances 67,000,000   50,800,000      
Unbilled receivables 230,300,000   179,200,000      
Decrease in fair value of reporting units considered, for impairment calculation     10.00%      
Percent change in contract estimates impact on operating results is less than this percentage 5.00%          
Change orders and/or claims 53,000,000   75,500,000      
Fiber Optic Licensing Terms, Minimum in years 5 years 5 years 5 years      
Fiber Optic Licensing Terms, Maximum in years 25 years 25 years 25 years      
Fiber optic deferred revenue 52,300,000   48,800,000      
Fiber optic non-current deferred revenue 44,300,000   40,200,000      
Total amount of unrecognized tax benefits relating to uncertain tax positions 53,200,000          
Amount of unrecognized tax benefits change from year-end relating to uncertain tax positions 4,400,000          
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months upper bound 11,000,000          
Restricted Stock Units to be Settled in Cash [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Number of common stock shares that may be received by RSU holder 1          
Sunrise Powerlink Project [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Revenue associated with change order $ 165,000,000   $ 165,000,000      
Minimum [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Equity method investment ownership 20.00%          
Minimum [Member] | Restricted Stock Units to be Settled in Cash [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Vesting period for restricted stock units to be settled in cash 2 years          
Maximum [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Equity method investment ownership 50.00%          
Maximum [Member] | Restricted Stock Units to be Settled in Cash [Member]
           
Summary Of Significant Accounting Policies [Line Items]            
Vesting period for restricted stock units to be settled in cash 3 years