Consolidated Statement of Stockholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income(Loss)	Total
Balance at the beginning of the period at Dec. 31, 2015					$ (61,505)
Increase (Decrease) in Stockholders' Equity
Net income						$ 70,663
Other comprehensive income					3,997
Balance at the end of the period at Jun. 30, 2016					(57,508)
Balance at the beginning of the period at Mar. 31, 2016					(60,352)
Increase (Decrease) in Stockholders' Equity
Net income						33,695
Other comprehensive income					2,844
Balance at the end of the period at Jun. 30, 2016					(57,508)
Balance at the beginning of the period at Dec. 31, 2016	$ 997	$ 291,908	$ 1,135,694	$ (531,268)	(53,329)	844,002
Balance (in shares) at Dec. 31, 2016	99,701
Increase (Decrease) in Stockholders' Equity
Adoption of share-based compensation guidance on January 1, 2017		3,504	(2,200)			1,304
Net income			56,363			56,363
Recognition of equity compensation		25,325	297			25,622
Net issuance/forfeiture of nonvested shares		(38,161)		38,161
Dividends accrued, $0.92 per share			(77,457)			(77,457)
Repurchase of common stock				(12,013)		(12,013)
Other comprehensive income					6,347	6,347
Balance at the end of the period at Jun. 30, 2017	$ 997	282,576	1,112,697	(505,120)	(46,982)	844,168
Balance (in shares) at Jun. 30, 2017	99,701
Balance at the beginning of the period at Dec. 31, 2016						10,653
Increase (Decrease) in Redeemable Noncontrolling Interest
Net income						1,136
Net redemption and deconsolidation of redeemable noncontrolling interests in sponsored funds						16,929
Balance at the end of the period at Jun. 30, 2017						28,718
Balance at the beginning of the period at Mar. 31, 2017					(48,944)
Increase (Decrease) in Stockholders' Equity
Net income						23,307
Other comprehensive income					1,962
Balance at the end of the period at Jun. 30, 2017	$ 997	$ 282,576	$ 1,112,697	$ (505,120)	$ (46,982)	844,168
Balance (in shares) at Jun. 30, 2017	99,701
Balance at the end of the period at Jun. 30, 2017						$ 28,718