CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Transactional and maintenance		$ 195,195	$ 161,249	$ 369,857	$ 314,909
Professional services		46,078	41,284	88,704	84,827
License		16,585	25,845	34,618	48,242
Total revenues		257,858	228,378	493,179	447,978
Operating expenses:
Cost of revenues	[1]	78,519	72,131	152,878	142,128
Research and development		32,519	26,663	61,493	52,805
Selling, general and administrative	[1]	97,057	86,231	187,353	171,445
Amortization of intangible assets	[1]	1,684	3,312	3,472	6,632
Total operating expenses		209,779	188,337	405,196	373,010
Operating income		48,079	40,041	87,983	74,968
Interest expense, net		(7,116)	(6,578)	(13,576)	(12,750)
Other income (expense), net		(161)	(327)	352	(427)
Income before income taxes		40,802	33,136	74,759	61,791
Provision for income taxes		8,527	8,052	15,185	(1,194)
Net income		32,275	25,084	59,574	62,985
Other comprehensive income (loss):
Foreign currency translation adjustments		9,125	6,089	12,196	(8,258)
Comprehensive income		$ 41,400	$ 31,173	$ 71,770	$ 54,727
Earnings per share:
Basic (in dollars per share)		$ 1.08	$ 0.81	$ 1.98	$ 2.03
Diluted (in dollars per share)		$ 1.03	$ 0.78	$ 1.90	$ 1.94
Shares used in computing earnings per share:
Basic (in shares)		29,985	31,017	30,032	31,003
Diluted (in shares)		31,300	32,260	31,431	32,398

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 4.