Business segment information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business segment information [Line Items]
Number of reportable business segments									3
Number of businesses reclassified in segment reporting									2
Businesses reclassified in segement reporting, revenue										$ 22,745	$ 13,982
Businesses reclassified in segement reporting, operating income										1,109	468
Depreciation and amortization expense related to corporate assets which was allocated to segments									$ 32,505	34,801	37,893
Total revenue from external customers:	$ 463,510	$ 439,816	$ 435,874	$ 433,617	$ 448,513	$ 413,204	$ 405,410	$ 406,955	1,772,817	1,674,082	1,584,824
Operating income:									354,331	332,633	317,914
Depreciation and amortization expense:									76,700	65,842	64,473
Asset impairment charges						$ 6,468			0	6,468	5,000
Total assets:	1,844,402				1,688,391				1,844,402	1,688,391	1,569,529
Capital asset purchases:									$ 43,261	$ 41,119	$ 37,459
Customer concentration risk [Member]
Business segment information [Line Items]
Percentage of concentration risk									10.00%	10.00%	10.00%
Checks [Member]
Business segment information [Line Items]
Total revenue from external customers:									$ 873,298	$ 870,910	$ 884,605
Small Business Services [Member] | Checks [Member] | Product concentration risk [Member]
Business segment information [Line Items]
Percentage of concentration risk									40.10%
Financial Services [Member] | Checks [Member] | Customer concentration risk [Member]
Business segment information [Line Items]
Percentage of concentration risk									59.70%
Direct Checks [Member] | Checks [Member] | Customer concentration risk [Member]
Business segment information [Line Items]
Percentage of concentration risk									84.60%
Reportable business segments [Member] | Small Business Services [Member]
Business segment information [Line Items]
Total revenue from external customers:									$ 1,151,916	1,106,505	1,036,268
Operating income:									203,933	187,226	175,420
Depreciation and amortization expense:									45,513	44,418	45,329
Asset impairment charges									0	6,468	5,000
Total assets:	995,445				949,521				995,445	949,521	942,048
Capital asset purchases:									0	0	0
Reportable business segments [Member] | Financial Services [Member]
Business segment information [Line Items]
Total revenue from external customers:									455,390	391,129	357,142
Operating income:									91,539	87,908	82,811
Depreciation and amortization expense:									26,807	14,675	11,231
Asset impairment charges									0	0	0
Total assets:	435,632				274,086				435,632	274,086	111,432
Capital asset purchases:									0	0	0
Reportable business segments [Member] | Direct Checks [Member]
Business segment information [Line Items]
Total revenue from external customers:									165,511	176,448	191,414
Operating income:									58,859	57,499	59,683
Depreciation and amortization expense:									4,380	6,749	7,913
Asset impairment charges									0	0	0
Total assets:	161,987				164,171				161,987	164,171	167,283
Capital asset purchases:									0	0	0
Corporate [Member]
Business segment information [Line Items]
Total revenue from external customers:									0	0	0
Operating income:									0	0	0
Depreciation and amortization expense:									0	0	0
Asset impairment charges									0	0	0
Total assets:	$ 251,338				$ 300,613				251,338	300,613	348,766
Capital asset purchases:									$ 43,261	$ 41,119	$ 37,459