CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUES
Commissions and fees	$ 1,762,787	$ 1,656,951	$ 1,567,460
Investment income	1,456	1,004	747
Other income, net	2,386	2,554	7,589
Total revenues	1,766,629	1,660,509	1,575,796
EXPENSES
Employee compensation and benefits	925,217	856,952	811,112
Non-cash stock-based compensation	16,052	15,513	19,363
Other operating expenses	262,872	251,055	235,328
(Gain)/loss on disposal	(1,291)	(619)	47,425
Amortization	86,663	87,421	82,941
Depreciation	21,003	20,890	20,895
Interest	39,481	39,248	28,408
Change in estimated acquisition earn-out payables	9,185	3,003	9,938
Total expenses	1,343,130	1,257,950	1,236,047
Income before income taxes	423,499	402,559	339,749
Income taxes	166,008	159,241	132,853
Net income	$ 257,491	$ 243,318	$ 206,896
Net income per share:
Basic (in dollars per share)	$ 1.84	$ 1.72	$ 1.43
Diluted (in dollars per share)	1.82	1.70	1.41
Dividends declared per share (in dollars per share)	$ 0.5025	$ 0.4525	$ 0.41