Supplemental balance sheet information (available-for-sale securities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Available-for-sale securities [Line Items]
Cost	$ 64,493		$ 27,427
Gross unrealized gains	0		0
Gross unrealized losses	(356)		(115)
Fair value	64,137		27,312
Funds held for customers, cash	15,621		27,340
Expected maturities of available-for-sale securities
Due in one year or less	54,355
Due in two to five years	3,695
Due in six to ten years	6,087
Total available-for-sale securities	64,137
Funds held for customers [Member]
Available-for-sale securities [Line Items]
Cost	15,494	[1]	15,915	[2]
Gross unrealized gains	0	[1]	0	[2]
Gross unrealized losses	(356)	[1]	(115)	[2]
Fair value	15,138	[1]	15,800	[2]
Funds held for customers [Member] | Canadian and provincial government securities [Member]
Available-for-sale securities [Line Items]
Cost	10,159		10,371
Gross unrealized gains	0		0
Gross unrealized losses	(356)		(115)
Fair value	9,803		10,256
Funds held for customers [Member] | Canadian guaranteed investment certificate [Member]
Available-for-sale securities [Line Items]
Cost	5,335		5,544
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Fair value	5,335		5,544
Cash equivalents [Member] | Money market securities [Member]
Available-for-sale securities [Line Items]
Cost	46,900		9,350
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Fair value	46,900		9,350
Other current assets [Member] | Canadian money market fund [Member]
Available-for-sale securities [Line Items]
Cost	2,099		2,162
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Fair value	$ 2,099		$ 2,162

[1] Funds held for customers, as reported on the consolidated balance sheet as of September 30, 2013, also included cash of $15,621.

[2] Funds held for customers, as reported on the consolidated balance sheet as of December 31, 2012, also included cash of $27,340.