Fair Value of Financial Instruments (Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2017
Derivatives:
Increase/(decrease) in contingent consideration value	$ (800)	$ 400
Fair value adjustment of minority owned equity investment	0	$ (2,300)
Interest Rate Swap
Derivatives:
Asset for Swaps			$ 600
Recurring
Financial Assets:
Cash and cash equivalents	152,822		105,185
Restricted cash	9,892		10,517
Other investments	2,232		1,898
Total	164,946		117,600
Financial Liabilities:
Contingent consideration	3,700		4,509
Total debt	1,688,230		1,690,731
Total	1,691,930		1,695,240
Recurring | Interest Rate Swap
Derivatives:
Asset for Swaps			572
Derivative Liability	96,272		47,691
Recurring | Level 1
Financial Assets:
Cash and cash equivalents	152,822		105,185
Restricted cash	8,196		9,791
Other investments	0		0
Total	161,018		114,976
Financial Liabilities:
Contingent consideration	0		0
Total debt	0		0
Total	0		0
Recurring | Level 1 | Interest Rate Swap
Derivatives:
Asset for Swaps			0
Derivative Liability	0		0
Recurring | Level 2
Financial Assets:
Cash and cash equivalents	0		0
Restricted cash	1,696		726
Other investments	2,232		1,898
Total	3,928		2,624
Financial Liabilities:
Contingent consideration	0		0
Total debt	1,688,230		1,690,731
Total	1,688,230		1,690,731
Recurring | Level 2 | Interest Rate Swap
Derivatives:
Asset for Swaps			572
Derivative Liability	96,272		47,691
Recurring | Level 3
Financial Assets:
Cash and cash equivalents	0		0
Restricted cash	0		0
Other investments	0		0
Total	0		0
Financial Liabilities:
Contingent consideration	3,700		4,509
Total debt	0		0
Total	3,700		4,509
Recurring | Level 3 | Interest Rate Swap
Derivatives:
Asset for Swaps			0
Derivative Liability	$ 0		$ 0
Myriad Development, Inc. & Insignificant Acquisition
Financial Liabilities:
Contingent consideration				$ 6,200
Maximum | Myriad Development, Inc. & Insignificant Acquisition
Financial Liabilities:
Contingent consideration				$ 20,500