Fair value measurements (other financial instruments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Carrying value
Fair value measurements, other financial instruments [Line Items]
Cash (excluding cash equivalents)	$ 51,088		$ 36,085
Cash (funds held for customers)	27,689		27,340
Loans and notes receivable from distributors	18,047		19,843
Long-term debt, including portion due within one year	638,787	[1]	652,581
Fair value
Fair value measurements, other financial instruments [Line Items]
Cash (excluding cash equivalents)	51,088		36,085
Cash (funds held for customers)	27,689		27,340
Loans and notes receivable from distributors	17,051		19,170
Long-term debt, including portion due within one year	684,133	[1]	676,859
Quoted prices in active markets for identical assets (Level 1)
Fair value measurements, other financial instruments [Line Items]
Cash (excluding cash equivalents)	51,088		36,085
Cash (funds held for customers)	27,689		27,340
Loans and notes receivable from distributors	0		0
Long-term debt, including portion due within one year	684,133	[1]	481,048
Significant other observable inputs (Level 2)
Fair value measurements, other financial instruments [Line Items]
Cash (excluding cash equivalents)	0		0
Cash (funds held for customers)	0		0
Loans and notes receivable from distributors	0		0
Long-term debt, including portion due within one year	0	[1]	195,811
Significant unobservable inputs (Level 3)
Fair value measurements, other financial instruments [Line Items]
Cash (excluding cash equivalents)	0		0
Cash (funds held for customers)	0		0
Loans and notes receivable from distributors	17,051		19,170
Long-term debt, including portion due within one year	$ 0	[1]	$ 0

[1] Amounts exclude capital lease obligations.