Stock-Based Compensation Plans (Narrative) (Details) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2012 $ / shares shares
Common share authorized under Convergys LTIP	38.0
Stock options, common shares to be issued upon exercise	0.5	0.7	0.8	1.2
Total stock, common shares to be issued upon exercise	2.7
Options approved, weighted average exercise price | $ / shares	$ 13.33	$ 13.24	$ 13.11	$ 12.91
Options approved, common shares available, future issuance	7.4
Stock-based compensation expense | $	$ 16,900,000	$ 10,200,000	$ 13,400,000
Awards Classified as Liabilities [Domain]
Stock-based compensation expense | $	$ 1,200,000	1,800,000
Stock Options [Member]
Stock options, common shares to be issued upon exercise	0.5
Options approved, weighted average exercise price | $ / shares	$ 13.33
Options approved, common shares available, future issuance	0.0
Weighted average grant date, fair value, options outstanding | $ / shares	$ 3.78
Weighted average grant date, fair value, options exercisable | $ / shares	$ 3.74
Aggregate intrinsic value, stock options exercised | $	$ 2,700,000	1,100,000	1,300,000
Recognized tax benefit from exercised stock | $	600,000	$ 200,000	$ 300,000
Aggregate intrinsic value, stock options outstanding and exercisable | $	$ 5,300,000
Stock Options [Member] | Maximum [Member]
Award Vesting Period	3 years
Stock Options [Member] | Minimum [Member]
Award Vesting Period	2 years
Time-Based Restricted Stock [Member]
Restricted stock units, common shares to be issed upon exercise	1.3	1.3	1.4	1.6
Granted, shares	0.7	0.7	0.6
Restricted stock units granted, weighted average fair value at date of grant | $ / shares	$ 22.41	$ 20.55	$ 16.35
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ / shares	$ 20.20	$ 17.66	$ 14.62	$ 13.04
Total unrecognized compensation cost related to non-vested restricted stock and restricted stock units | $	$ 15,100,000
Weighted average recognition period (in years)	1.0
Restricted Stock Units (RSUs) [Member]
Restricted stock units, common shares to be issed upon exercise	2.2
Options approved, weighted average exercise price | $ / shares	$ 0.00
Options approved, common shares available, future issuance	0.0
Aggregate intrinsic value, non-vested restricted stock | $	$ 41,100,000
Performance Shares [Member]
Restricted stock units, common shares to be issed upon exercise	0.3	0.0	0.3	1.0
Granted, shares	0.3	0.0	0.1
Restricted stock units granted, weighted average fair value at date of grant | $ / shares	$ 21.84	$ 0.00	$ 16.34
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ / shares	$ 21.84	$ 0.00	$ 12.90	$ 12.69
Performance Shares [Member] | Maximum [Member]
Payout range	200.00%
Performance Shares [Member] | Minimum [Member]
Payout range	50.00%
2013 Performance grants [Domain] | Performance Shares [Member]
Total unrecognized compensation cost related to non-vested restricted stock and restricted stock units | $	$ 0.1
2012 Stock Option Grants [Member] | Stock Options [Member]
Stock option expense | $	$ 100,000	$ 200,000	$ 600,000
Options granted, weighted-average grant date fair value | $ / shares				3.43
Strike price | $ / shares				$ 12.79
Expected volatility				30.74%
Expected term (in years)				4 years 6 months
Risk-free interest rate				0.76%
Expected dividend rate				0.00%
Key terms not yet established [Member] | Performance Shares [Member]
Granted, shares	0.4
Various Dates [Domain] | Performance Shares [Member]
Granted, shares		0.3	0.4