BUSINESS SEGMENT INFORMATION (disaggregated revenue information) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Product and service information [Line Items]
Total revenue	$ 454,492	$ 439,461	$ 410,405	$ 486,423	$ 522,071	$ 493,593	$ 493,986	$ 499,065	$ 1,790,781	$ 2,008,715	$ 1,998,025
U. S. [Member]
Product and service information [Line Items]
Total revenue									1,678,187	1,888,036	1,871,375
Foreign, primarily Canada and Australia [Member]
Product and service information [Line Items]
Total revenue									112,594	120,679	126,650
Reportable business segments [Member] | Payments [Member]
Product and service information [Line Items]
Total revenue									301,901	269,573	224,546
Reportable business segments [Member] | Payments [Member] | U. S. [Member]
Product and service information [Line Items]
Total revenue									266,920	233,152	188,156
Reportable business segments [Member] | Payments [Member] | Foreign, primarily Canada and Australia [Member]
Product and service information [Line Items]
Total revenue									34,981	36,421	36,390
Reportable business segments [Member] | Cloud Solutions [Member]
Product and service information [Line Items]
Total revenue									252,773	318,383	307,589
Reportable business segments [Member] | Cloud Solutions [Member] | U. S. [Member]
Product and service information [Line Items]
Total revenue									220,699	283,695	269,919
Reportable business segments [Member] | Cloud Solutions [Member] | Foreign, primarily Canada and Australia [Member]
Product and service information [Line Items]
Total revenue									32,074	34,688	37,670
Reportable business segments [Member] | Promotional Solutions [Member]
Product and service information [Line Items]
Total revenue									529,649	640,892	658,357
Reportable business segments [Member] | Promotional Solutions [Member] | U. S. [Member]
Product and service information [Line Items]
Total revenue									506,240	613,830	629,592
Reportable business segments [Member] | Promotional Solutions [Member] | Foreign, primarily Canada and Australia [Member]
Product and service information [Line Items]
Total revenue									23,409	27,062	28,765
Reportable business segments [Member] | Checks [Member]
Product and service information [Line Items]
Total revenue									706,458	779,867	807,533
Reportable business segments [Member] | Checks [Member] | U. S. [Member]
Product and service information [Line Items]
Total revenue									684,328	757,359	783,708
Reportable business segments [Member] | Checks [Member] | Foreign, primarily Canada and Australia [Member]
Product and service information [Line Items]
Total revenue									22,130	22,508	23,825
Checks [Member]
Product and service information [Line Items]
Total revenue									706,458	779,867	807,533
Checks [Member] | Reportable business segments [Member] | Checks [Member]
Product and service information [Line Items]
Total revenue									706,458	779,867	807,533
Forms and other products [Member]
Product and service information [Line Items]
Total revenue									316,245	348,757	357,700
Forms and other products [Member] | Reportable business segments [Member] | Promotional Solutions [Member]
Product and service information [Line Items]
Total revenue									316,245	348,757	357,700
Treasury management solutions [Member]
Product and service information [Line Items]
Total revenue									226,105	193,527	148,011
Treasury management solutions [Member] | Reportable business segments [Member] | Payments [Member]
Product and service information [Line Items]
Total revenue									226,105	193,527	148,011
Marketing and promotional solutions [Member]
Product and service information [Line Items]
Total revenue									213,404	292,135	300,657
Marketing and promotional solutions [Member] | Reportable business segments [Member] | Promotional Solutions [Member]
Product and service information [Line Items]
Total revenue									213,404	292,135	300,657
Web and hosted solutions [Member]
Product and service information [Line Items]
Total revenue									133,618	156,097	156,164
Web and hosted solutions [Member] | Reportable business segments [Member] | Cloud Solutions [Member]
Product and service information [Line Items]
Total revenue									133,618	156,097	156,164
Data-driven marketing solutions [Member]
Product and service information [Line Items]
Total revenue									119,155	162,286	151,425
Data-driven marketing solutions [Member] | Reportable business segments [Member] | Cloud Solutions [Member]
Product and service information [Line Items]
Total revenue									119,155	162,286	151,425
Other payments solutions [Member]
Product and service information [Line Items]
Total revenue									75,796	76,046	76,535
Other payments solutions [Member] | Reportable business segments [Member] | Payments [Member]
Product and service information [Line Items]
Total revenue									$ 75,796	$ 76,046	$ 76,535