CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Noncontrolling Interest Non Redeemable
Beginning balance, Amount at Dec. 31, 2017	$ 506,591	$ 226	$ (42,249)	$ 126,490	$ 364,401	$ 57,723
Beginning balance, Shares at Dec. 31, 2017		22,640,046
Beginning balance, Treasury Shares at Dec. 31, 2017	(4,890,504)		(4,890,504)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 23,779				21,792	1,987
Acquired noncontrolling interest	36,474					36,474
Noncontrolling Interest Distributions	(1,119)					(1,119)
Sale of noncontrolling interest	2,907			(2,664)		5,571
Nonvested stock compensation	3,919			3,919
Issuance of vested stock	0	$ 2		(2)
Issuance of vested stock, Shares		176,385
Treasury shares redeemed to pay income tax	(4,095)		$ (4,095)
Stock Issued During Period, Value, Acquisitions	795,405	$ 127
Acquired Noncontrolling Interest Redeemable	$ 3,428
Stock Issued During Period, Shares, Acquisitions		12,765,288
Adjustments to Additional Paid in Capital, Other				795,278
Treasury shares redeemed to pay income tax, Shares	(63,161)		(63,161)
Issuance of common stock under Employee Stock Purchase Plan	$ 634			634
Issuance of common stock under Employee Stock Purchase Plan, Shares		10,705
Ending balance, Amount at Jun. 30, 2018	$ 1,364,495	$ 355	$ (46,344)	$ 923,655	$ 386,193	$ 100,636
Ending balance, Shares at Jun. 30, 2018		35,592,424
Ending balance, Treasury Shares at Jun. 30, 2018	(4,953,665)		(4,953,665)