Other Employee Benefits - Schedule of Shares Purchased in Open Market for Employees (Details) - USD ($)													12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense													$ 5,960,000	$ 7,180,000	$ 6,246,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares (in shares)	3,339	4,511	2,465	2,905	2,475	2,779	1,661	1,931	3,065	4,613	3,535	4,161	13,220	8,846	15,374
Common Stock Fair Value (in dollars per share)	$ 27.39	$ 22.34	$ 29.35	$ 30.74	$ 28.46	$ 32.17	$ 43.15	$ 42.15	$ 25.80	$ 21.15	$ 23.65	$ 22.90	$ 26.77	$ 35.37	$ 23.13
Purchase Price (in dollars per share)	$ 23.28	$ 18.99	$ 24.94	$ 26.13	$ 24.19	$ 27.34	$ 36.68	$ 35.83	$ 21.93	$ 17.98	$ 20.10	$ 19.47	$ 22.75	$ 30.07	$ 19.66
Compensation Expense	$ 13,723	$ 15,116	$ 10,873	$ 13,395	$ 10,566	$ 13,410	$ 10,751	$ 12,209	$ 11,862	$ 14,623	$ 12,549	$ 14,272	$ 53,107	$ 46,936	$ 53,306