Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 2,462,237	$ 2,058,625	$ 2,353,959	$ 1,990,239
Other comprehensive income (loss) before reclassifications			(11,260)	145
Amounts reclassified from accumulated other comprehensive income (loss)			103	12
Total other comprehensive income (loss)	290	(437)	(11,157)	157
Balance at end of period	2,583,070	2,116,928	2,583,070	2,116,928
Unrealized Gains (Losses) on Available-for-Sale Debt Investments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			21	0
Other comprehensive income (loss) before reclassifications			(98)	369
Amounts reclassified from accumulated other comprehensive income (loss)			52	(11)
Total other comprehensive income (loss)			(46)	358
Balance at end of period	(25)	358	(25)	358
Defined Benefit Pension
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(4,218)	(4,820)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive income (loss)			51	23
Total other comprehensive income (loss)			51	23
Balance at end of period	(4,167)	(4,797)	(4,167)	(4,797)
Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			31,467	23,935
Other comprehensive income (loss) before reclassifications			(11,162)	(224)
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Total other comprehensive income (loss)			(11,162)	(224)
Balance at end of period	20,305	23,711	20,305	23,711
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	15,823	19,709	27,270	19,115
Total other comprehensive income (loss)	290	(437)	(11,157)	157
Balance at end of period	$ 16,113	$ 19,272	$ 16,113	$ 19,272