Selected Quarterly Operating Results (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Revenues:
Software, hardware and supplies	$ 17,109		$ 21,899		$ 23,720		$ 25,844		$ 26,562		$ 35,074		$ 31,860		$ 28,911		$ 88,572	$ 122,407	$ 106,514
Implementation and training services	7,161		7,266		8,535		12,046		8,270		6,555		6,094		5,472		35,008	26,391	18,015
System sales	24,270		29,165		32,255		37,890		34,832		41,629		37,954		34,383		123,580	148,798	124,529
Maintenance	40,025		39,463		38,715		38,568		35,871		36,245		35,214		31,502		156,771	138,832	110,019
Electronic data interchange services	15,653		15,209		15,024		13,823		13,081		12,101		11,985		12,092		59,709	49,259	41,022
Revenue cycle management and related services	15,317		15,015		14,486		14,401		11,402		11,147		11,142		11,881		59,219	45,572	45,065
Other services	16,030		15,658		15,648		13,614		13,808		11,643		11,339		10,584		60,950	47,374	32,728
Maintenance, EDI, RCM and other services	87,025		85,345		83,873		80,406		74,162		71,136		69,680		66,059		336,649	281,037	228,834
Total revenues	111,295		114,510		116,128		118,296		108,994		112,765		107,634		100,442		460,229	429,835	353,363
Cost of revenue:
Software, hardware and supplies	5,695		4,660		5,624		5,771		4,976		4,622		4,187		4,614		21,750	18,399	19,779
Implementation and training services	7,023		7,221		7,507		9,145		6,179		5,994		5,050		4,075		30,896	21,298	15,010
Total cost of system sales	12,718		11,881		13,131		14,916		11,155		10,616		9,237		8,689		52,646	39,697	34,789
Maintenance	5,505		5,259		4,741		4,811		4,844		4,412		3,994		3,854		20,316	17,104	12,948
Electronic data interchange services	10,099		9,852		9,151		9,248		8,606		7,890		7,964		7,962		38,350	32,422	27,711
Revenue cycle management and related services	10,980		10,918		10,556		10,870		8,608		8,405		8,456		8,826		43,324	34,295	33,815
Other services	8,995		8,686		8,785		8,550		8,728		7,011		6,369		5,597		35,016	27,705	18,219
Total cost of maintenance, EDI, RCM and other services	35,579		34,715		33,233		33,479		30,786		27,718		26,783		26,239		137,006	111,526	92,693
Total cost of revenue	48,297		46,596		46,364		48,395		41,941		38,334		36,020		34,928		189,652	151,223	127,482
Gross profit	62,998		67,914		69,764		69,901		67,053		74,431		71,614		65,514		270,577	278,612	225,881
Operating expenses:
Selling, general and administrative	38,308		35,532		37,832		36,681		34,195		33,096		32,169		29,386		148,353	128,846	108,310
Research and development costs	8,231		7,786		6,272		8,576		8,907		8,277		7,358		6,827		30,865	31,369	21,797
Amortization of acquired intangible assets	1,194		1,212		1,316		1,137		653		543		520		482		4,859	2,198	1,682
Impairment of goodwill	17,400		0		0		0		0		0		0		0		17,400	0	0
Total operating expenses	65,133		44,530		45,420		46,394		43,755		41,916		40,047		36,695		201,477	162,413	131,789
Income from operations	(2,135)		23,384		24,344		23,507		23,298		32,515		31,567		28,819		69,100	116,199	94,092
Interest income	(93)		13		(62)		35		35		55		75		82		(107)	247	263
Other income (expense), net	36		(122)		220		(213)		261		(218)		(144)		(38)		(79)	(139)	61
Income before provision for income taxes	(2,192)		23,275		24,502		23,329		23,594		32,352		31,498		28,863		68,914	116,307	94,416
Provision for income taxes	1,898		7,649		8,811		7,832		8,521		11,247		11,002		9,880		26,190	40,650	32,810
Net income	$ (4,090)		$ 15,626		$ 15,691		$ 15,497		$ 15,073		$ 21,105		$ 20,496		$ 18,983		$ 42,724	$ 75,657	$ 61,606
Net income per share:
Basic	$ (0.07)	[1]	$ 0.26	[1]	$ 0.26	[1]	$ 0.26	[1]	$ 0.26	[1]	$ 0.36	[1]	$ 0.35	[1]	$ 0.33	[1]	$ 720.00	$ 1,290.00	$ 1,060.00
Diluted	$ (0.07)	[1]	$ 0.26	[1]	$ 0.26	[1]	$ 0.26	[1]	$ 0.25	[1]	$ 0.36	[1]	$ 0.35	[1]	$ 0.32	[1]	$ 720.00	$ 1,280.00	$ 1,060.00
Weighted-average shares outstanding:
Basic	59,541		59,400		59,347		59,281		59,048		58,847		58,511		58,362		59,392	58,729	57,894
Diluted	59,541		59,405		59,386		59,388		59,232		59,128		58,902		58,800		59,462	59,049	58,236
Dividends declared per common share	$ 0		$ 0		$ 0		$ 0		$ 0		$ 0		$ 0		$ 0		$ 700	$ 700	$ 625

[1] Quarterly EPS may not sum to annual EPS due to rounding