CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands		Total	Common Stock	Treasury	Additional Paid-In Capital	Retained Earnings	Noncontrolling Interest Non Redeemable
Beginning balance, Amount at Dec. 31, 2019		$ 1,507,251	$ 361	$ (60,060)	$ 949,321	$ 523,701	$ 93,928
Beginning balance (in shares) at Dec. 31, 2019			36,129,280
Beginning balance, treasury (in shares) at Dec. 31, 2019				5,136,890
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	[1]	24,123				22,024	2,099
Acquired noncontrolling interest		2,880					2,880
Noncontrolling interest distributions		(2,093)					(2,093)
Purchase of additional controlling interest		(23,575)			(2,470)		(21,105)
Nonvested stock compensation		3,680			3,680
Issuance of vested stock		2	$ 2
Issuance of vested stock (in shares)			163,163
Treasury shares redeemed to pay income tax		(6,933)		$ (7,122)	189
Treasury shares redeemed to pay income tax (in shares)				59,390
Issuance of common stock under Employee Stock Purchase Plan (in shares)			4,663
Issuance of common stock under Employee Stock Purchase Plan		610			610
Ending balance, Amount at Mar. 31, 2020		1,505,945	$ 363	$ (67,182)	951,330	545,725	75,709
Ending balance (in shares) at Mar. 31, 2020			36,297,106
Ending balance, treasury (in shares) at Mar. 31, 2020				5,196,280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to noncontrolling interest-redeemable		3,600
Beginning balance, Amount at Dec. 31, 2020		$ 1,613,354	$ 364	$ (69,011)	962,120	635,297	84,584
Beginning balance (in shares) at Dec. 31, 2020			36,355,497
Beginning balance, treasury (in shares) at Dec. 31, 2020		5,215,657		5,215,657
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	[2]	$ 39,128				34,659	4,469
Noncontrolling interest distributions		(2,417)					(2,417)
Purchase of additional controlling interest		(142)			(81)		(61)
Sale of noncontrolling interest		138					138
Nonvested stock compensation		3,513			3,513
Issuance of vested stock		1	$ 1
Issuance of vested stock (in shares)			148,447
Treasury shares redeemed to pay income tax		$ (9,541)		$ (9,541)
Treasury shares redeemed to pay income tax (in shares)				51,221
Issuance of common stock under Employee Stock Purchase Plan (in shares)		3,204	3,204
Issuance of common stock under Employee Stock Purchase Plan		$ 649			649
Ending balance, Amount at Mar. 31, 2021		$ 1,644,683	$ 365	$ (78,552)	$ 966,201	$ 669,956	$ 86,713
Ending balance (in shares) at Mar. 31, 2021			36,507,148
Ending balance, treasury (in shares) at Mar. 31, 2021		5,266,878		5,266,878
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to noncontrolling interest-redeemable		$ 2,305

[1] Net income excludes net income attributable to noncontrolling interest-redeemable of $3.6 million during the three months ended March 31, 2020. Noncontrolling interest-redeemable is reflected outside of permanent equity on the condensed consolidated balance sheets. See Note 8 of the Notes to Condensed Consolidated Financial Statements.

[2] Net income excludes net income attributable to noncontrolling interest-redeemable of $2.3 million during the three months ended March 31, 2021. Noncontrolling interest-redeemable is reflected outside of permanent equity on the condensed consolidated balance sheets. See Note 8 of the Notes to Condensed Consolidated Financial Statements.