CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands		Total	Common Stock	Treasury	Additional Paid-In Capital	Retained Earnings	Noncontrolling Interest Non Redeemable	Net Equity [Member]
Beginning balance, Amount at Dec. 31, 2017		$ 506,591	$ 226	$ (42,249)	$ 126,490	$ 364,401	$ 57,723
Beginning balance (in shares) at Dec. 31, 2017			22,640,046
Beginning balance, Treasury (in shares) at Dec. 31, 2017				4,890,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	5,592				4,995	597
Acquired noncontrolling interest		1,235					1,235
Noncontrolling interest distributions		(615)					(615)
Sale of noncontrolling interest					(2,029)		5,583	$ 3,554
NCI acquired, net of sales					(44)		(12)	$ (56)
Nonvested stock compensation		1,601			1,601
Restricted share grants			$ 2		(2)
Restricted stock vesting (in shares)			165,567
Treasury shares redeemed to pay income tax		(3,467)		$ (3,467)	0
Treasury shares redeemed to pay income tax (in shares)				56,772
Issuance of common stock under Employee Stock Purchase Plan		332	$ 0		332
Issuance of common stock under Employee Stock Purchase Plan (in shares)			5,534
Ending balance, Amount at Mar. 31, 2018		514,767	$ 228	$ (45,716)	126,348	369,396	64,511
Ending balance (in shares) at Mar. 31, 2018			22,811,147
Ending balance, Treasury (in shares) at Mar. 31, 2018				4,947,276
Beginning balance, Amount at Dec. 31, 2018		$ 1,424,474	$ 356	$ (49,374)	937,968	427,975	107,549
Beginning balance (in shares) at Dec. 31, 2018			35,636,414
Beginning balance, Treasury (in shares) at Dec. 31, 2018		(4,958,721)		4,958,721
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	$ 20,542				18,856	1,686
Acquired noncontrolling interest		820					820
Noncontrolling interest distributions		(6,799)					(6,799)
NCI acquired, net of sales		(18,000)					(18,000)
Nonvested stock compensation		1,804			1,804
Restricted share grants		2	$ 2		0
Restricted stock vesting (in shares)			174,562
Treasury shares redeemed to pay income tax		$ (7,692)		$ (7,577)	(115)
Treasury shares redeemed to pay income tax (in shares)		(59,967)		85,509
Issuance of common stock under Employee Stock Purchase Plan		$ 478	$ 0		478
Issuance of common stock under Employee Stock Purchase Plan (in shares)		5,357	5,357
Ending balance, Amount at Mar. 31, 2019		$ 1,415,629	$ 358	$ (56,951)	$ 940,135	$ 446,831	$ 85,256
Ending balance (in shares) at Mar. 31, 2019			35,816,333
Ending balance, Treasury (in shares) at Mar. 31, 2019		(5,044,230)		5,044,230

[1] Net income excludes net income attributable to noncontrolling interest-redeemable of $2.9 million and $2.4 million during the three months ending March 31, 2019 and 2018, respectively. 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.