Condensed Consolidated Statements of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Parent [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Cross Currency Interest Rate Contract [Member] Common Stock [Member]	Cross Currency Interest Rate Contract [Member] Additional Paid-in Capital [Member]	Cross Currency Interest Rate Contract [Member] Retained Earnings [Member]	Cross Currency Interest Rate Contract [Member] AOCI Attributable to Parent [Member]	Cross Currency Interest Rate Contract [Member] Parent [Member]	Cross Currency Interest Rate Contract [Member] Noncontrolling Interest [Member]	Cross Currency Interest Rate Contract [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2019								51,032														51,032
Balance in Other comprehensive income (loss) beginning of period at Dec. 31, 2019	$ 0	$ 0	$ (755)	$ 0	$ (755)	$ 0	$ (755)	$ 51	$ 913,150	$ 487,118	$ (8,654)	$ 1,391,665	$ 122,990	$ 1,514,655								$ 51	$ 913,150	$ 487,873	$ (8,654)	$ 1,392,420	$ 122,990	$ 1,515,410
Stock-based compensation																						$ 0	1,989	0	0	1,989	0	1,989
Exercise of stock-based awards by employees and directors (in shares)																						4
Exercise of stock-based awards by employees and directors																						$ 0	0	0	0	0	0	0
Cash paid to noncontrolling interest																						0	0	0	0	0	(3,007)	(3,007)
Cash dividend declared																						0	0	(5,614)	0	(5,614)	0	(5,614)
Increase in noncontrolling interest																						0	0	0	0	0	1,447	1,447
Net income																						0	0	26,033	0	26,033	3,543	29,576
Foreign currency translation adjustments																						0	0	0	(258)	(258)	(387)	(645)
Change in respect of derivative instruments designated for cash flow hedge															$ 0	$ 0	$ 0	$ 13	$ 13	$ 0	$ 13							0
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment																						0	0	0	(4,755)	(4,755)	0	(4,755)
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																						$ 0	0	0	(8)	(8)	0	(8)
Change in unrealized gains or losses on marketable securities available-for-sale (net of related tax of $0)																												0
Other comprehensive income (loss)																												5
Balance (in shares) at Mar. 31, 2020																						51,036
Balance in Other comprehensive income (loss) end of period at Mar. 31, 2020																						$ 51	915,139	507,537	(13,662)	1,409,065	124,586	1,533,651
Balance (in shares) at Dec. 31, 2020																						55,983
Balance in Other comprehensive income (loss) beginning of period at Dec. 31, 2020																						$ 56	1,262,446	550,103	(6,620)	1,805,985	135,452	1,941,437
Stock-based compensation																						$ 0	2,097	0	0	2,097	0	2,097
Exercise of stock-based awards by employees and directors (in shares)																						1
Exercise of stock-based awards by employees and directors																						$ 0	0	0	0	0	0	0
Cash paid to noncontrolling interest																						0	0	0	0	0	(3,898)	(3,898)
Cash dividend declared																						0	0	(6,718)	0	(6,718)	0	(6,718)
Net income																						0	0	15,259	0	15,259	2,290	17,549
Foreign currency translation adjustments																						0	0	0	(1,253)	(1,253)	(573)	(1,826)
Change in respect of derivative instruments designated for cash flow hedge															$ 0	$ 0	$ 0	$ (2,798)	$ (2,798)	$ 0	$ (2,798)							(2,798)
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment																						0	0	0	3,755	3,755	0	3,755
Stock issuance costs reimbursement																						0	285	0	0	285	0	285
Change in unrealized gains or losses on marketable securities available-for-sale (net of related tax of $0)																						0	0	0	(20)	(20)	0	(20)
Other comprehensive income (loss)																						$ 0	0	0	16	16	0	16
Balance (in shares) at Mar. 31, 2021																						55,984
Balance in Other comprehensive income (loss) end of period at Mar. 31, 2021																						$ 56	$ 1,264,828	$ 558,644	$ (6,920)	$ 1,816,608	$ 133,271	$ 1,949,879