Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	$ (5,489)	$ 9,505
Amount reclassified from accumulated other comprehensive loss	(176)	2,138
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 1,600
Treasury Lock [Member]
Derivative [Line Items]
Derivative, Inception Date	Dec. 06, 2018
Derivative, Maturity Date	Jun. 28, 2019
Derivative, Notional Amount	$ 250,000
Derivative, Description of Variable Rate Basis	30 year U.S. Treasury
Derivative, Fixed Interest Rate	3.147%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0
Interest Rate Cash Flow Hedge Liability at Fair Value			$ (5,491)
Derivative $300M Term [Member]
Derivative [Line Items]
Derivative, Inception Date	Apr. 03, 2017
Derivative, Maturity Date	Dec. 02, 2020
Derivative, Notional Amount	$ 300,000
Derivative, Description of Variable Rate Basis	1 Month LIBOR with Floor
Derivative, Fixed Interest Rate	1.824%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ (2,255)		(3,759)
Derivatives 200K @ 1.04770% and 65K @ 1.07000% [Member] [Domain]
Derivative [Line Items]
Derivative, Inception Date	Aug. 01, 2016
Derivative, Maturity Date	Jan. 05, 2022
Derivative, Notional Amount	$ 265,000
Derivative, Description of Variable Rate Basis	1 Month LIBOR with Floor
Derivative, Fixed Interest Rate	1.053%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ (8,110)		(10,838)
Derivative @ 1.30250% 20.0M [Member]
Derivative [Line Items]
Derivative, Inception Date	Apr. 07, 2016
Derivative, Maturity Date	Apr. 01, 2023
Derivative, Notional Amount	$ 20,000
Derivative, Description of Variable Rate Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.3025%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ (626)		(880)
Derivative $33M Swap [Member]
Derivative [Line Items]
Derivative, Inception Date	Dec. 01, 2016
Derivative, Maturity Date	Nov. 01, 2023
Derivative, Notional Amount	$ 33,000
Derivative, Description of Variable Rate Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.49%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ (918)		(1,376)
Derivative @ 2.36600% 37.5K [Member] [Domain]
Derivative [Line Items]
Derivative, Inception Date	Jun. 02, 2017
Derivative, Maturity Date	Jun. 02, 2027
Derivative, Notional Amount	$ 37,500
Derivative, Description of Variable Rate Basis	1 Month LIBOR with Floor
Derivative, Fixed Interest Rate	2.366%
Interest Rate Cash Flow Hedge Asset at Fair Value			(629)
Interest Rate Cash Flow Hedge Liability at Fair Value	$ (224)
Swap [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	7,100
Fair Value, Measurements, Recurring [Member]
Derivative [Line Items]
Interest Rate Cash Flow Hedge Asset at Fair Value	(11,909)		(17,482)
Interest Rate Cash Flow Hedge Liability at Fair Value	(224)		(5,491)
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Derivative [Line Items]
Interest Rate Cash Flow Hedge Asset at Fair Value	(11,909)		(17,482)
Interest Rate Cash Flow Hedge Liability at Fair Value	(224)		(5,491)
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	11,685		$ 11,991
Parent Company [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(5,489)	9,505
Interest Expense	$ 37,752	$ 36,785