Credit Facility (Details) - USD ($) $ in Millions	Oct. 30, 2015	Jun. 30, 2016	Dec. 31, 2015
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
BANK OF AMERICA - MERRILL LYNCH ATS [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding		$ 3.3
Credit Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding		$ 25.9
Debt Instrument, Interest Rate, Effective Percentage		1.71%
Credit Agreement [Member] | BANK OF AMERICA - MERRILL LYNCH ATS [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding			$ 18.8
Letters of credit outstanding			3.3
Remaining borrowing capacity		$ 116.2	$ 120.7
October 2015 Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 150.0
Current borrowing capacity, percent of eligible unbilled accounts receivable less certain reserves	80.00%
Current borrowing capacity, percent of eligible billed accounts receivable	85.00%
Line of Credit Facility, Optional Additional Borrowing Capacity	$ 75.0
October 2015 Line of Credit [Member] | Swingline Loans [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	30.0
October 2015 Line of Credit [Member] | Letter of Credit [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 20.0
Maximum [Member] | Credit Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		1.76%
Maximum [Member] | October 2015 Line of Credit [Member] | Swingline Loans [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity, percent of eligible unbilled accounts receivable less certain reserves	30.00%
UNITED STATES | October 2015 Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 122.5
CANADA | October 2015 Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	15.0
UNITED KINGDOM | October 2015 Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 12.5