Accounts Receivable (Details) (USD $)	Jun. 30, 2013	Jun. 30, 2012
Accounts Receivable [Abstract]
Allowance for doubtful accounts receivable	$ 3,200,000	$ 3,600,000
Billed receivables	468,254,000	481,268,000
Billable receivables at end of period	102,963,000	84,243,000
Unbilled receivables pending receipt of contractual documents authorizing billing	43,399,000	63,331,000
Total accounts receivable, current	614,616,000	628,842,000
Unbilled receivables, retainages and fee withholdings expected to be billed beyond the next 12 months	11,330,000	9,942,000
Total accounts receivable	$ 625,946,000	$ 638,784,000